Fix Dialect doc generation to special case for the Builtin dialect empty name

[mehdi_amini]

Summary

This should fix the issue with an empty entry for the builtin dialect on
the website.

[rriddle]

mlir/tools/mlir-tblgen/OpDocGen.cpp

226

Don't wrap the Builtin in quotes, it gives the wrong impression given that this isn't the namespace of the dialect.

[mehdi_amini]

Do not put "Builtin" in quotes

[jpienaar]

Thanks :)

mlir/tools/mlir-tblgen/OpDocGen.cpp

 
 //===----------------------------------------------------------------------===//
 // Dialect Documentation
 //===----------------------------------------------------------------------===//
 
 static void emitDialectDoc(const Dialect &dialect, ArrayRef<Operator> ops,
                            ArrayRef<Type> types, ArrayRef<TypeDef> typeDefs,
                            raw_ostream &os) {
-  os << "# '" << dialect.getName() << "' Dialect\n\n";
+  os << "# ";
+  if (dialect.getName().empty())
+    os << "Builtin";
+  else
+    os << "'" << dialect.getName() << "'";
+  os << " Dialect\n\n";
   emitIfNotEmpty(dialect.getSummary(), os);
   emitIfNotEmpty(dialect.getDescription(), os);
 
   os << "[TOC]\n\n";
 
   // TODO: Add link between use and def for types
   if (!types.empty()) {
     os << "## Type constraint definition\n\n";