[clang] [libclang/python] Add deprecation warnings to CompletionChunk.isKind methods (PR #177854)

[Vlad Serebrennikov via cfe-commits]

================
@@ -3157,19 +3157,55 @@ def string(self) -> CompletionString | None:
             return None
         return CompletionString(res)
 
+    __deprecation_message = (
+        "'CompletionChunk.{}' will be removed in a future release. "
+        "All uses of 'CompletionChunk.{}' should be replaced by checking "
+        "if the 'CompletionChunk's kind is 'CompletionChunkKind.{}'."
----------------
Endilll wrote:

```suggestion
        "if 'CompletionChunk.kind` is equal to 'CompletionChunkKind.{}'."
```

https://github.com/llvm/llvm-project/pull/177854