[libclang] Tweaks for clang_CXXMethod_isExplicit

This adds a release note that was accidentally dropped, and moves the
symbol from LLVM 16 to LLVM 17 in the module map.

Amends 0a51bc7

Author: AaronBallman

clang/docs/ReleaseNotes.rst

@@ -213,6 +213,10 @@ clang-extdef-mapping
 libclang
 --------
 
+- Introduced the new function ``clang_CXXMethod_isExplicit``,
+  which identifies whether a constructor or conversion function cursor
+  was marked with the explicit identifier.
+
 Static Analyzer
 ---------------
 

clang/tools/libclang/libclang.map

@@ -416,6 +416,9 @@ LLVM_16 {
     clang_disposeAPISet;
     clang_getSymbolGraphForCursor;
     clang_getSymbolGraphForUSR;
+};
+
+LLVM_17 {
     clang_CXXMethod_isExplicit;
 };