[clang-tools-extra] Fix #41439: Update the documentation with the correct information. (PR #69377)

[Piotr Zegar via cfe-commits]

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@@ -10,7 +10,12 @@ Guide:
 
 https://google.github.io/styleguide/cppguide.html#Function_Declarations_and_Definitions
 
-All parameters should be named, with identical names in the declaration and
-implementation.
+A parameter name may be omitted only if the parameter is not used in the
----------------
PiotrZSL wrote:

Maybe:
```
All parameters should have the same name in both the function declaration and definition.
If a parameter is not utilized, its name can be commented out in a function definition.
```

https://github.com/llvm/llvm-project/pull/69377