[clang-tools-extra] [clang-tidy] check `std::string_view` and custom string-like classes in `readability-string-compare` (PR #88636)

[via cfe-commits]

================
@@ -50,5 +52,36 @@ Examples:
   }
 
 The above code examples show the list of if-statements that this check will
-give a warning for. All of them uses ``compare`` to check if equality or
+give a warning for. All of them use ``compare`` to check equality or
 inequality of two strings instead of using the correct operators.
+
+Options
+-------
+
+.. option:: StringLikeClasses
+
+   A string containing semicolon-separated names of string-like classes.
+   By default contains only ``::std::basic_string``
+   and ``::std::basic_string_view``. If a class from this list has
+   a ``compare`` method similar to that of ``std::string``, it will be checked
+   in the same way.
+
+Example
+^^^^^^^
+
+.. code-block:: c++
+
+  struct CustomString {
+  public:
+    int compare (const CustomString& other) const;
+  }
+
+  CustomString str1;
+  CustomString str2;
+
+  // use str1 != str2 instead.
+  if (str1.compare(str2)) {
+  }
+
+If `StringLikeClasses` contains ``CustomString``, the check will suggest
----------------
EugeneZelenko wrote:

```suggestion
If `StringLikeClasses` contains `CustomString`, the check will suggest
```

https://github.com/llvm/llvm-project/pull/88636