Say default queries are all in security-extended suite (github#20363)

Author: eroullit

data/reusables/code-scanning/codeql-query-suites.md

@@ -1,4 +1,4 @@
   | Query suite | Description |
   | :- | :- |
-  | `security-extended` | Queries of lower severity and precision than the default queries |
+  | `security-extended` | Queries from the default suite, plus lower severity and precision queries |
   | `security-and-quality` | Queries from `security-extended`, plus maintainability and reliability queries |