Make documentation/settings more discoverable

[kaddkaka]

What page or section of the docs have an issue?
Is it possible to add tags or hidden text to the documentation to make it easier to find specific pages? Took me 5 searches to find https://wezfurlong.org/wezterm/config/lua/config/selection_word_boundary.html?h=word even though I knew it existed.

Reasons:

1. The title "selection_word_boundary" was not included in search match
2. "boundary" doesn't match "boundaries" (stupid english)
3. delimiter was not used in the description

[wez]

While we're waiting for this upstream issue:

• Search: index document by custom metadata squidfunk/mkdocs-material#3174

You can add tags, see https://raw.githubusercontent.com/wez/wezterm/main/docs/config/lua/config/adjust_window_size_when_changing_font_size.md for an example. Tags show up at the top of doc pages and link to a tag index: https://wezfurlong.org/wezterm/tags.html#font

Please feel empowered to submit PRs to various doc pages to add tags, preferably in alignment with existing tags
You can test doc changes locally by running ci/build-docs.sh serve