Diagnostic for `static nonmutating` should be improved

[AnthonyLatsis]

Description

No response

Reproduction

struct S {
  nonmutating static func foo() {}
}

430 | 
431 | struct S {
432 |   nonmutating static func foo() {}
    |   `- error: static functions must not be declared mutating [static_functions_not_mutating]
433 | }
434 | 

Expected behavior

An example approach to improving this error message is to list both modifiers.

We can also tailor it to call out the modifier in question as it currently does in the case of mutating. The drawback of this option is that it conveys less information about language grammar.s

Environment

Swift version 6.1-dev (26e888e)

Additional information

No response

[zvyaan]

Hi there,

I'd like to be assigned this issue, will try to work on it soon!

[devnumber7]

Hello,

I would like to work on it as my first issue !

[vlkhvnn]

Hello, I would like to work on this issue as my first one, very excited!

[AnthonyLatsis]

Hi folks, this issue is already assigned.