minor: Add basic editorconfig and pre-commit hooks to enforce style for whitespaces (#1926)

.github/pull_request_template.md

@@ -12,4 +12,4 @@
 
 - [ ] Format your code according to the [Contributor Guide](https://github.com/sgl-project/sglang/blob/main/docs/contributor_guide.md).
 - [ ] Add unit tests as outlined in the [Contributor Guide](https://github.com/sgl-project/sglang/blob/main/docs/contributor_guide.md).
-- [ ] Update documentation as needed, including docstrings or example tutorials.
+- [ ] Update documentation as needed, including docstrings or example tutorials.