[clang-tools-extra] [clang-tidy] Refactor: removed typos in 'AllowedTypes' option in various checks (PR #122957)

[Nicolas van Kempen via cfe-commits]

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@@ -31,6 +31,6 @@ Options
    A semicolon-separated list of names of types allowed to be copied in each
    iteration. Regular expressions are accepted, e.g. `[Rr]ef(erence)?$` matches
    every type with suffix `Ref`, `ref`, `Reference` and `reference`. The default
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nicovank wrote:

IMO it also makes sense to double tick the regex (so everything here). Probably slightly easier on the eyes as a code block when generated than an italicized string.,

https://github.com/llvm/llvm-project/pull/122957