## Summary of the Pull Request

- Renames `NavigatablePage` to `NavigablePage` to fix a spelling error.
- Reverts related entries in `exclude.txt` that triggered a forbidden
pattern error in the spell checker.
- The spell checker does not allow PascalCase words like
`NavigatablePage` in `exclude.txt` because of its automatic casing
rules.

 
Regression: #41285

---------

Co-authored-by: vanzue <vanzue@outlook.com>

## Summary of the Pull Request
Adds search functionality to the settings UI. This is added to an
`AutoSuggestBox` in the main `NavigationView`. Invoking a result
navigates to the proper location in the settings UI and focuses the
setting, when possible.

## References and Relevant Issues
Based on microsoft/PowerToys#41285

## Detailed Description of the Pull Request / Additional comments
- tools/GenerateSettingsIndex.ps1: parses all the XAML files in the
settings UI for SettingsContainers and builds a search index from them
- XAML changes: ensures all SettingContainer objects have an `x:Name` so
that we can navigate to them and bring them into view.
- TerminalSettingsEditor/Utils.h: implements `BringIntoViewWhenLoaded()`
which navigates to the relevant part of the UI. This is called in
`OnNavigatedTo()` for each page.
- fzf was moved out of TerminalApp so that TerminalSettingsEditor can
access it
- There's a few main components to searching, all of it is in
`MainPage`:
- `MainPage::_UpdateSearchIndex()`|`SearchIndex::Reset()`: loads the
search index generated by `GenerateSettingsIndex.ps1`; provides
additional localization, if needed
   - `MainPage::SettingsSearchBox_TextChanged`:
      - detect that text changed in the search box
- perform the actual search in `SearchIndex::SearchAsync()`. This is a
HEFTY async function that can be cancelled. It needs a lot of context
passed in to expand the search index appropriately (i.e. build awareness
of "PowerShell" profile and generate results appropriately). This is
also where fzf is used to perform weighted matching.
- the weighted matching itself is pretty complicated, but all the
associated bonus weights are at the top of SearchIndex.cpp.
- `SettingsSearchBox_QuerySubmitted`: extract the search index metadata
and call the correct `_Navigate()` function

## Validation Steps Performed
Search for...
- settings that don't change at runtime:
   - [x] global settings
   - [x] settings in profile.defaults
   - [x] "add new profile" page
- settings that may change at runtime:
   - [x] settings in a profile
   - [x] individual color schemes
   - [x] actions (main actions page + edit action subpage)
   - [x] new tab menu folders
   - [x] extensions
- misc. corner cases:
- [x] terminal chat (blocked in indexing script; requires minor changes
in feature branch)
   - [x] settings in appearance objects

To test fzf matching and weighted results, I specifically tested these
scenarios:
- "PowerShell" --> prioritize the PowerShell profile page(s)
- "font size" --> prioritize profile defaults entry
- "font size powershell" --> prioritize PowerShell > font size

## PR Checklist
Closes #12949 

## Follow-ups
- search by JSON key: need a way to add JSON keys to index entries.
`GetSearchableFields()` should make the rest pretty easy.
- search by keywords: need to define keywords. `GetSearchableFields()`
should make the rest pretty easy.