[clang] [TySan] Add initial documentation for Type Sanitizer (PR #123595)

[Aaron Ballman via cfe-commits]

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@@ -0,0 +1,162 @@
+================
+TypeSanitizer
+================
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AaronBallman wrote:

```suggestion
=============
TypeSanitizer
=============
```

https://github.com/llvm/llvm-project/pull/123595