add link to repo (#4622)

Author: billy-the-fish

use-timescale/extensions/pg-textsearch.md

@@ -12,7 +12,7 @@ import IntegrationPrereqs from "versionContent/_partials/_integration-prereqs.md
 # Optimize full text search with BM25 
 
 $PG full-text search at scale consistently hits a wall where performance degrades catastrophically. 
-$COMPANY's pg_textsearch brings modern [BM25][bm25-wiki]-based full-text search directly into $PG,
+$COMPANY's [pg_textsearch][pg_textsearch-github-repo] brings modern [BM25][bm25-wiki]-based full-text search directly into $PG,
 with a memtable architecture for efficient indexing and ranking. `pg_textsearch` integrates seamlessly with SQL and 
 provides better search quality and performance than the $PG built-in full-text search.
 
@@ -334,3 +334,5 @@ These limitations will be addressed in upcoming releases with disk-based segment
 [connect-using-psql]: /integrations/:currentVersion:/psql/#connect-to-your-service
 [recip-rank-fusion]: https://en.wikipedia.org/wiki/Mean_reciprocal_rank
 [pg-vectorscale]: /ai/:currentVersion:/sql-interface-for-pgvector-and-timescale-vector/#installing-the-pgvector-and-pgvectorscale-extensions
+[pg_textsearch-github-repo]: https://github.com/timescale/pg_textsearch
+