C++: Update supported compiler versions

Author: jketema

docs/codeql/reusables/supported-versions-compilers.rst

@@ -4,9 +4,9 @@
    :stub-columns: 1
 
    Language,Variants,Compilers,Extensions
-   C/C++,"C89, C99, C11, C17, C23, C++98, C++03, C++11, C++14, C++17, C++20, C++23 [1]_ [2]_ [3]_","Clang (including clang-cl [4]_ and armclang) extensions (up to Clang 19.1.0),
+   C/C++,"C89, C99, C11, C17, C23, C++98, C++03, C++11, C++14, C++17, C++20, C++23 [1]_ [2]_ [3]_","Clang (including clang-cl [4]_ and armclang) extensions (up to Clang 21),
 
-   GNU extensions (up to GCC 15.0),
+   GNU extensions (up to GCC 15),
 
    Microsoft extensions (up to VS 2022),