docs: only try to format tracked files

Don't format generated docs; their inputs should be formatted instead.

refs: wezterm#2273
refs: wezterm#2253

ci/build-docs.sh

@@ -1,4 +1,10 @@
 #!/bin/bash
+
+tracked_markdown=$(git ls-tree -r HEAD --name-only docs | egrep '\.(markdown|md)$')
+
+gelatyx lua --file $tracked_markdown --language-config ci/stylua.toml
+gelatyx lua --file $tracked_markdown --language-config ci/stylua.toml --check || exit 1
+
 set -x
 
 [[ -f /tmp/wezterm.releases.json ]] || curl https://api.github.com/repos/wez/wezterm/releases > /tmp/wezterm.releases.json
@@ -7,8 +13,6 @@ python3 ci/subst-release-info.py || exit 1
 python3 ci/generate-docs.py || exit 1
 mdbook-mermaid install docs
 mdbook build docs
-gelatyx lua --file docs/**/*.md --language-config ci/stylua.toml
-gelatyx lua --file docs/**/*.md --language-config ci/stylua.toml --check
 
 rm gh_pages/html/README.markdown
 cp assets/fonts/Symbols-Nerd-Font-Mono.ttf gh_pages/html/fonts/