[clang] [Clang][Comments] Allow HTML tags across multiple lines (PR #120843)

[via cfe-commits]

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@@ -1453,6 +1453,129 @@ TEST_F(CommentLexerTest, HTML19) {
   ASSERT_EQ(tok::newline,      Toks[2].getKind());
 }
 
+TEST_F(CommentLexerTest, HTML20) {
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cor3ntin wrote:

can we add tests for 
```<
a
>
```
To make sure we don;t do something unreasonable - even though it's not a valid tag?

https://github.com/llvm/llvm-project/pull/120843