Fix Wdocumentation "unknown parameter". NFC.

Author: RKSimon

clang/include/clang/Lex/HeaderSearch.h

@@ -670,9 +670,6 @@ class HeaderSearch {
 
   /// Retrieve all the modules corresponding to the given file.
   ///
-  /// \param AllowCreation Whether to allow inference of a new submodule, or to
-  ///        only return existing known modules.
-  ///
   /// \ref findModuleForHeader should typically be used instead of this.
   ArrayRef<ModuleMap::KnownHeader>
   findAllModulesForHeader(FileEntryRef File) const;