better name for a function in compilerplugins

The function is not just about a spelling location.

Change-Id: I96e9e9ef7e27a9763397b4b86473c1c30d0e3eeb
Reviewed-on: https://gerrit.libreoffice.org/80381
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

compilerplugins/clang/constfields.cxx

@@ -233,7 +233,7 @@ MyFieldInfo ConstFields::niceName(const FieldDecl* fieldDecl)
 
     SourceLocation expansionLoc
         = compiler.getSourceManager().getExpansionLoc(fieldDecl->getLocation());
-    StringRef name = getFileNameOfSpellingLoc(expansionLoc);
+    StringRef name = getFilenameOfLocation(expansionLoc);
     aInfo.sourceLocation
         = std::string(name.substr(strlen(SRCDIR) + 1)) + ":"
           + std::to_string(compiler.getSourceManager().getSpellingLineNumber(expansionLoc));