[clang] [clang][Parser] "Better" error messages for invalid template template (PR #95726)

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<!--LLVM CODE FORMAT COMMENT: {clang-format}-->


:warning: C/C++ code formatter, clang-format found issues in your code. :warning:

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``````````bash
git-clang-format --diff 9f69e116a55dbd36e2f4fde38317de7262c88d7c 44620330cd5238de549d3d77ddc447cd3bc51e60 -- clang/lib/Parse/ParseTemplate.cpp clang/test/CXX/drs/cwg1xx.cpp clang/test/Parser/cxx-template-decl.cpp
``````````

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View the diff from clang-format here.
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``````````diff
diff --git a/clang/lib/Parse/ParseTemplate.cpp b/clang/lib/Parse/ParseTemplate.cpp
index e5308d9eda..858a22f43a 100644
--- a/clang/lib/Parse/ParseTemplate.cpp
+++ b/clang/lib/Parse/ParseTemplate.cpp
@@ -787,18 +787,17 @@ NamedDecl *Parser::ParseTemplateTemplateParameter(unsigned Depth,
                                                   unsigned Position) {
   assert(Tok.is(tok::kw_template) && "Expected 'template' keyword");
 
-  if (Token ahead = GetLookAheadToken(1);
-      ahead.isOneOf(tok::identifier, tok::ellipsis,
-                    tok::equal, tok::comma,
-                    tok::greater, tok::greatergreater, tok::greatergreatergreater)) {
-    // Maybe they intended `typename` instead of `template` (given thats more common)
-    // Error early, to add a fixit hint
+  if (Token ahead = GetLookAheadToken(1); ahead.isOneOf(
+          tok::identifier, tok::ellipsis, tok::equal, tok::comma, tok::greater,
+          tok::greatergreater, tok::greatergreatergreater)) {
+    // Maybe they intended `typename` instead of `template` (given thats more
+    // common) Error early, to add a fixit hint
 
     Diag(ahead.getLocation(), diag::err_expected_less_after) << "template";
-    
+
     Diag(Tok.getLocation(), diag::note_meant_to_use_typename)
-      << FixItHint::CreateReplacement(CharSourceRange::getTokenRange(Tok.getLocation()),
-                                      "typename");
+        << FixItHint::CreateReplacement(
+               CharSourceRange::getTokenRange(Tok.getLocation()), "typename");
 
     Tok.setKind(tok::kw_typename);
     return ParseTypeParameter(Depth, Position);

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https://github.com/llvm/llvm-project/pull/95726