[clang] [clang] Enable descriptions for --print-supported-extensions (PR #66715)

[David Spickett via cfe-commits]

================
@@ -22,7 +23,8 @@ struct RISCVExtensionInfo {
   unsigned MinorVersion;
 };
 
-void riscvExtensionsHelp();
+void getAllExtensions(StringMap<RISCVExtensionInfo> &Features);
----------------
DavidSpickett wrote:

This can go if you just set the description of only one extension in the tests.

https://github.com/llvm/llvm-project/pull/66715