python: Enhance syntax highlighting for type hints (#18185)

Release Notes:

- Python: Improved syntax highlighting for type hints.

# Before

![image](https://github.com/user-attachments/assets/876a69ab-a572-4d1b-af99-e6f85f249ea6)

# After

![image](https://github.com/user-attachments/assets/4fb98a9b-bc5d-4799-b535-057047884383)

---
Why manual recursion?
- Due to tree-sitter grammar not supporting recursion in query
(https://github.com/tree-sitter-grammars/tree-sitter-lua/issues/24),
currently only manual recursion is possible (refer to
https://github.com/projekt0n/github-nvim-theme/pull/250/files).

<br/>

Unable to highlight when simple structures appear before complex
structures, example:
```python
def t() -> str | dict[int, dict[int, dict[int, str]]]:
    pass
```
Because complex structures are parsed as `subscript` rather than
`generic_type` by tree-sitter in this case ☹

<br/>

Related:

- https://github.com/zed-industries/zed/issues/14715
- [Union Type (Python
Doc)](https://docs.python.org/3/library/stdtypes.html#union-type)
- [Type parameter lists (Python
Doc)](https://docs.python.org/3/reference/compound_stmts.html#type-parameter-lists)

---------

Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

crates/languages/src/python/highlights.scm

@@ -1,5 +1,14 @@
 (attribute attribute: (identifier) @property)
 (type (identifier) @type)
+(generic_type (identifier) @type)
+
+; Type alias
+(type_alias_statement "type" @keyword)
+
+; TypeVar with constraints in type parameters
+(type
+  (tuple (identifier) @type)
+)
 
 ; Function calls