Add support for disabling nesting in the sinppets menu

Adds a `nesting` param to `showSuggestions`. The default remains `"enabled"`. We now also accept `"disabled"`, which will plop all the snippets into a single top-level list. This will make it easier for users to open suggestions based on what they've already typed at the commandline. e.g. type `gitco` at the commandline, and have that pre-filtered to the `git commit -m ""\u001b[D` snippet.

As spec'd in [Suggestions-UI.md](https://github.com/microsoft/terminal/blob/main/doc/specs/%231595%20-%20Suggestions%20UI/Suggestions-UI.md)

src/cascadia/TerminalApp/AppActionHandlers.cpp

@@ -1360,7 +1360,7 @@ namespace winrt::TerminalApp::implementation
                 // their settings file. Ask the ActionMap for those.
                 if (WI_IsFlagSet(source, SuggestionsSource::Tasks))
                 {
-                    const auto tasks = _settings.GlobalSettings().ActionMap().FilterToSendInput(currentCommandline);
+                    const auto tasks = _settings.GlobalSettings().ActionMap().FilterToSendInput(currentCommandline, realArgs.Nesting());
                     for (const auto& t : tasks)
                     {
                         commandsCollection.push_back(t);

src/cascadia/TerminalSettingsModel/ActionArgs.h

@@ -216,8 +216,9 @@ protected:                                                                  \
     X(CommandPaletteLaunchMode, LaunchMode, "launchMode", false, CommandPaletteLaunchMode::Action)
 
 ////////////////////////////////////////////////////////////////////////////////
-#define SUGGESTIONS_ARGS(X)                                                 \
-    X(SuggestionsSource, Source, "source", false, SuggestionsSource::Tasks) \
+#define SUGGESTIONS_ARGS(X)                                                       \
+    X(SuggestionsSource, Source, "source", false, SuggestionsSource::Tasks)       \
+    X(SuggestionsNesting, Nesting, "nesting", false, SuggestionsNesting::Enabled) \
     X(bool, UseCommandline, "useCommandline", false, false)
 
 ////////////////////////////////////////////////////////////////////////////////

src/cascadia/TerminalSettingsModel/ActionArgs.idl

@@ -122,6 +122,12 @@ namespace Microsoft.Terminal.Settings.Model
         All = 0xffffffff,
     };
 
+    enum SuggestionsNesting
+    {
+        Disabled,
+        Enabled,
+    };
+
     interface INewContentArgs {
         String Type { get; };
         Boolean Equals(INewContentArgs other);
@@ -343,8 +349,9 @@ namespace Microsoft.Terminal.Settings.Model
     [default_interface] runtimeclass SuggestionsArgs : IActionArgs
     {
         SuggestionsArgs();
-        SuggestionsArgs(SuggestionsSource source, Boolean useCommandline);
+        SuggestionsArgs(SuggestionsSource source, SuggestionsNesting nesting, Boolean useCommandline);
         SuggestionsSource Source { get; };
+        SuggestionsNesting Nesting { get; };
         Boolean UseCommandline { get; };
     };
 

src/cascadia/TerminalSettingsModel/ActionMap.cpp

@@ -806,7 +806,8 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
     }
 
     IVector<Model::Command> _filterToSendInput(IMapView<hstring, Model::Command> nameMap,
-                                               winrt::hstring currentCommandline)
+                                               winrt::hstring currentCommandline,
+                                               Model::SuggestionsNesting nesting)
     {
         auto results = winrt::single_threaded_vector<Model::Command>();
 
@@ -861,20 +862,30 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
             else if (command.HasNestedCommands())
             {
                 // Look for any sendInput commands nested underneath us
-                auto innerResults = _filterToSendInput(command.NestedCommands(), currentCommandline);
+                auto innerResults = _filterToSendInput(command.NestedCommands(), currentCommandline, nesting);
 
                 if (innerResults.Size() > 0)
                 {
                     // This command did have at least one sendInput under it
+                    if (nesting == Model::SuggestionsNesting::Enabled)
+                    {
+                        // Create a new Command, which is a copy of this Command,
+                        // which only has SendInputs in it
+                        winrt::com_ptr<implementation::Command> cmdImpl;
+                        cmdImpl.copy_from(winrt::get_self<implementation::Command>(command));
+                        auto copy = cmdImpl->Copy();
+                        copy->NestedCommands(innerResults.GetView());
 
-                    // Create a new Command, which is a copy of this Command,
-                    // which only has SendInputs in it
-                    winrt::com_ptr<implementation::Command> cmdImpl;
-                    cmdImpl.copy_from(winrt::get_self<implementation::Command>(command));
-                    auto copy = cmdImpl->Copy();
-                    copy->NestedCommands(innerResults.GetView());
-
-                    results.Append(*copy);
+                        results.Append(*copy);
+                    }
+                    else if (nesting == Model::SuggestionsNesting::Disabled)
+                    {
+                        // Just add all the nested commands directly to the list we're going to return
+                        for (const auto& nested : innerResults)
+                        {
+                            results.Append(nested);
+                        }
+                    }
                 }
             }
         }
@@ -883,8 +894,9 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
     }
 
     IVector<Model::Command> ActionMap::FilterToSendInput(
-        winrt::hstring currentCommandline)
+        winrt::hstring currentCommandline,
+        Model::SuggestionsNesting nesting)
     {
-        return _filterToSendInput(NameMap(), currentCommandline);
+        return _filterToSendInput(NameMap(), currentCommandline, nesting);
     }
 }

src/cascadia/TerminalSettingsModel/ActionMap.h

@@ -83,7 +83,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         void ExpandCommands(const Windows::Foundation::Collections::IVectorView<Model::Profile>& profiles,
                             const Windows::Foundation::Collections::IMapView<winrt::hstring, Model::ColorScheme>& schemes);
 
-        winrt::Windows::Foundation::Collections::IVector<Model::Command> FilterToSendInput(winrt::hstring currentCommandline);
+        winrt::Windows::Foundation::Collections::IVector<Model::Command> FilterToSendInput(winrt::hstring currentCommandline, Model::SuggestionsNesting nesting);
 
     private:
         Model::Command _GetActionByID(const winrt::hstring& actionID) const;

src/cascadia/TerminalSettingsModel/ActionMap.idl

@@ -22,7 +22,7 @@ namespace Microsoft.Terminal.Settings.Model
 
         IVector<Command> ExpandedCommands { get; };
 
-        IVector<Command> FilterToSendInput(String CurrentCommandline);
+        IVector<Command> FilterToSendInput(String CurrentCommandline, SuggestionsNesting nesting);
     };
 
     [default_interface] runtimeclass ActionMap : IActionMapView

src/cascadia/TerminalSettingsModel/TerminalSettingsSerializationHelpers.h

@@ -510,6 +510,14 @@ JSON_FLAG_MAPPER(::winrt::Microsoft::Terminal::Settings::Model::SuggestionsSourc
     };
 };
 
+JSON_ENUM_MAPPER(::winrt::Microsoft::Terminal::Settings::Model::SuggestionsNesting)
+{
+    JSON_MAPPINGS(2) = {
+        pair_type{ "enabled", ValueType::Enabled },
+        pair_type{ "disabled", ValueType::Disabled },
+    };
+};
+
 JSON_ENUM_MAPPER(::winrt::Microsoft::Terminal::Settings::Model::WindowingMode)
 {
     JSON_MAPPINGS(3) = {