Command palette search results should bold the matching text

[zadjii-msft]

Omitted from initial implementation in #6635.

I'm really unsure if this is possible in XAML, but hey, I think it would be important.

[DHowett]

If we're using TextBlocks we can just fill them with Runs generated at runtime 😄

[DHowett]

<TextBlock FontFamily="Segoe UI" FontSize="32">
  <Run FontWeight="Bold">N</Run><Run>ew</Run> <Run FontWeight="Bold">T</Run><Run>ab</Run>
</TextBlock>

[zadjii-msft]

Yes, that's easy enough, but then we need to hook up a lot more XAML - the Palette knows which characters need to be highlighted, so it would need to set that on each of the commands in the match list, then each of those guys would need to return a Run instead of just a string.

It's not impossible, but it's a lot more XAML binding than anything I've done