[clang-tools-extra] [clang-tidy][docs] Add documentation for Clang-Tidy Automation (PR #153166)

[Baranov Victor via cfe-commits]

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@@ -331,6 +331,104 @@ An overview of all the command-line options:
         some-check.SomeOption: 'some value'
       ...
 
+Clang-Tidy Automation
+=====================
+
+:program:`clang-tidy` can analyze multiple source files by specifying them on the
+command line. For larger projects, automation
+scripts provide additional functionality like parallel execution and integration
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vbvictor wrote:

make lines full, up to 80 characters

https://github.com/llvm/llvm-project/pull/153166