Fix const items not being allowed to be called `r#move` or `r#static` Because of an ambiguity with const closures, the parser needs to ensure that for a const item, the `const` keyword isn't followed by a `move` or `static` keyword, as that would indicate a const closure: ```rust fn main() { const move // ... } ``` This check did not take raw identifiers into account, therefore being unable to distinguish between `const move` and `const r#move`. The latter is obviously not a const closure, so it should be allowed as a const item. This fixes the check in the parser to only treat `const ...` as a const closure if it's followed by the *proper keyword*, and not a raw identifier. Additionally, this adds a large test that tests for all raw identifiers in all kinds of positions, including `const`, to prevent issues like this one from occurring again. fixes #137128