feat: allow attributes on all expressions

Attrs are syntactically valid on any expression, even if they are not
allowed semantically everywhere yet.

crates/parser/src/grammar.rs

@@ -63,7 +63,7 @@ pub(crate) mod entry_points {
     pub(crate) use types::type_;
 
     pub(crate) fn expr(p: &mut Parser) {
-        let _ = expressions::expr_with_attrs(p);
+        let _ = expressions::expr(p);
     }
 
     pub(crate) fn stmt(p: &mut Parser) {