Further optimize cross tile symbol index findMatches

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### ✨ Features and improvements
 - Text labels can now include relatively uncommon Chinese, Japanese, Korean, and Vietnamese characters, as well as characters from historical writing systems. When using server-side fonts, the map may request glyph PBFs beyond U+FFFF from the server instead of throwing an error as before. ([#6640](https://github.com/maplibre/maplibre-gl-js/pull/6640)) (by [@1ec5](https://github.com/1ec5))
+- Speed up the cross tile symbol index in certain circumstances ([#6641](https://github.com/maplibre/maplibre-gl-js/pull/6641)) (by [@bradymadden97](https://github.com/bradymadden97))
 - _...Add new stuff here..._
 
 ### 🐞 Bug fixes