[clang-tidy] Fix module registry name and description for Darwin clang-tidy module.

[mwyman]

Summary

When creating the module, must have copy-pasted from the misc module, and forgotten to update the name/description of the module in the registry.

clang-tools-extra/trunk/clang-tidy/darwin/DarwinTidyModule.cpp

CheckFactories.registerCheck<DispatchOnceNonstaticCheck>(
         "darwin-dispatch-once-nonstatic");
   }
 };
 
 } // namespace darwin
 
 // Register the DarwinTidyModule using this statically initialized variable.
 static ClangTidyModuleRegistry::Add<darwin::DarwinModule>
-    X("misc-module", "Adds miscellaneous lint checks.");
+    X("darwin-module", "Adds Darwin-specific lint checks.");
 
 // This anchor is used to force the linker to link in the generated object file
 // and thus register the DarwinModule.
 volatile int DarwinModuleAnchorSource = 0;
 
 } // namespace tidy
 } // namespace clang