Bump DIAG_SIZE_LEX since we've hit the limit downstream as of 1c4e0f6.

Author: dgg5503

clang/include/clang/Basic/DiagnosticIDs.h

@@ -37,7 +37,7 @@ namespace clang {
       DIAG_SIZE_DRIVER        =  400,
       DIAG_SIZE_FRONTEND      =  200,
       DIAG_SIZE_SERIALIZATION =  120,
-      DIAG_SIZE_LEX           =  400,
+      DIAG_SIZE_LEX           =  500,
       DIAG_SIZE_PARSE         =  700,
       DIAG_SIZE_AST           =  300,
       DIAG_SIZE_COMMENT       =  100,