Filter selection prompt items with search

[DanBiscotti]

fixes #1546

• I have read the Contribution Guidelines
• I have commented on the issue above and discussed the intended changes
• A maintainer has signed off on the changes and the issue was assigned to me
• All newly added code is adequately covered by tests
• All existing tests are still running without errors
• The documentation was modified to reflect the changes OR no documentation changes are required.

Changes

I changed the code so that now when a user searches, the list is filtered down to only those items which match the search term

ListPromptState.cs

There are now 3 lists which hold the current state of the prompt:

• Items This existed before and contains all the items
• VisibleItems This list contains only items which match the search term, or any groups which contain a child which matches the search term
• _selectableItems This list contains only the subset of VisibleItems which are selectable (ie. not a group if in leaf mode, following the same logic as before with _leafIndexes). it is a list of SelectableItem which contains the ListPromptItem and also the index of the item in VisibleItems.

VisibleItems and _selectableItems are updated every time the search term changes, when the user is navigates the list the only the index of the item in _selectableItems is updated (which is stored in _selectableIndex).

ListPrompt.cs

• BuildRenderable now uses VisibleItems
• added argument for filterOnSearch

SelectionPrompt.cs

• added FilterOnSearch property
• Removed the spacebar as a key which submits, to allow the search to contain spaces
• Added null check for when state.Current == null. This happens when the VisibleItems is filtered to the point it contains no items
• removed skipUnselectableItems argument as it wasn't being used

SelectionPromptExtensions.cs

• Added optional bool to the EnableSearch method to set FilterOnSearch

MultiSelectionPrompt.cs

• added argument for filterOnSearch
• removed skipUnselectableItems argument as it wasn't being used

IListPromptStrategy

• removed skipUnselectableItems argument as it wasn't being used

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Please upvote 👍 this pull request if you are interested in it.

[DanBiscotti]

I realize it's not perfect yet, but would be good to hear what you think of the idea, I haven't made a PR in the repo before so apologies if I've missed something!

[DanBiscotti]

@microsoft-github-policy-service agree

[arfazca]

Just wondering if there's any update on this? I'm currently working on a project that requires search functionality with spaces, so it would be great to have this merged. @DanBiscotti Appreciate your time and efforts on the project!