[Doc][IR] String attribute support in function parameters and functions

Hi All,

I’ve noticed that string attributes are supported for function parameters and functions, but this support is not mentioned in the language reference documentation. I’ve submitted a pull request to update the documentation. Could someone please review it if there are no issues? Thanks!

[Documentation] Update parameter and function attribute section in LangRef by rajatbajpai · Pull Request #114007 · llvm/llvm-project