docs: update documentation URL to fish.rootiest.fyi

Replaced all instances of fish-config.rootiest.fyi with the new domain fish.rootiest.fyi across the codebase.

docs/fish-config.1

@@ -2638,7 +2638,7 @@ that matches the keyword. Lookup order: docs/fish-config.index (exact
 keyword aliases), then a normalized heading scan as fallback.
 When opened with ov a sticky navigation hint is shown at the top of the
 screen. Section matching is case-insensitive. Pass --html / -w to open
-the published documentation website (https://fish-config.rootiest.fyi/)
+the published documentation website (https://fish.rootiest.fyi/)
 in the default browser via xdg-open \[em] deep links to a section aren\[aq]t
 supported there, so if a keyword is given a note points you to the site\[aq]s
 search box instead. Pass --man / -m to open the compiled man page
@@ -2929,7 +2929,7 @@ Notes:
 
 Example:
 open-url https://git.rootiest.dev/rootiest/fish-config
-open-url -v https://fish-config.rootiest.fyi/
+open-url -v https://fish.rootiest.fyi/
 \f[R]
 .fi
 .PP
@@ -4396,7 +4396,7 @@ help config --html
 \f[R]
 .fi
 .PP
-Opens https://fish-config.rootiest.fyi/ in the default browser \[em] the
+Opens https://fish.rootiest.fyi/ in the default browser \[em] the
 Starlight-powered site built from \f[V]docs/manual/**\f[R] on every push
 to \f[V]main\f[R].
 It has a section sidebar and full-text search.