Update contribution section

Most of the content in the contribution section was unnecessary ("open a
PR" is hardly unique instructions). More importantly, some potential
contributors were spending time on thoughtful and detailed explanations
on why `parser.c` should be checked in, not realizing that their efforts
are fruitless.

README.md

@@ -66,10 +66,9 @@ substitute `tree-sitter test` directly.
 
 ## Contributions
 
-If you have a change to make to this parser, and the change is a net positive, please submit a pull request. I mostly
-started this parser to teach myself how `tree-sitter` works, and how to write a grammar, so I welcome improvements. If
-you have an issue with the parser, please file a bug and include a test case to put in the `corpus`. I can't promise any
-level of support, but having the test case makes it more likely that I want to tinker with it.
+All contributions to this repository are welcome.
+
+If said contribution is to check generated files (e.g., `parser.c`) into the repository, be aware that your contribution will not be accepted. Make sure to read the [FAQ entry](https://github.com/alex-pinkus/tree-sitter-swift?tab=readme-ov-file#where-is-your-parserc) and the [prior](https://github.com/alex-pinkus/tree-sitter-swift/issues/362) [discussions](https://github.com/alex-pinkus/tree-sitter-swift/pull/315) and [compromises](https://github.com/alex-pinkus/tree-sitter-swift/issues/149) that have occurred already on this topic.
 
 ## Using tree-sitter-swift in Web Assembly 
 To use tree-sitter-swift as a language for the web bindings version  tree-sitter, which will likely be a more modern version than the published node