Merge #8776

8776: fix: fix unnecessary recomputations due to macros r=jonas-schievink a=jonas-schievink

This computes a macro's fragment kind eagerly (when the calling file is still available in parsed form) and stores it in the `MacroCallLoc`. This means that during expansion we no longer have to reparse the file containing the macro call, avoiding the unnecessary salsa dependencies (https://github.com/rust-analyzer/rust-analyzer/pull/8746#issuecomment-834776349).

Marking as draft until I manage to find a test for this problem, since for some reason `typing_inside_a_function_should_not_invalidate_expansions` does not catch this (which might indicate that I misunderstand the problem).

I've manually confirmed that this fixes the issue described in https://github.com/rust-analyzer/rust-analyzer/pull/8746#issuecomment-834776349:

```
    7ms - parse_query @ FileId(179)
   12ms - SourceBinder::to_module_def
       12ms - crate_def_map:wait
            5ms - item_tree_query (1 calls)
            7ms - ???
```

Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>

crates/hir_expand/src/builtin_macro.rs

@@ -578,6 +578,7 @@ mod tests {
                     krate,
                     kind: MacroCallKind::FnLike {
                         ast_id: AstId::new(file_id.into(), ast_id_map.ast_id(&macro_call)),
+                        fragment: FragmentKind::Expr,
                     },
                 };