Rollup merge of #107487 - edward-shen:edward-shen/107213-round-2, r=estebank

Make the "extra if in let...else block" hint a suggestion

Changes the hint to a suggestion, suggested in #107213.

r? ```@estebank```

compiler/rustc_parse/src/parser/expr.rs

@@ -2290,7 +2290,7 @@ impl<'a> Parser<'a> {
                 block
             } else {
                 let let_else_sub = matches!(cond.kind, ExprKind::Let(..))
-                    .then(|| IfExpressionLetSomeSub { if_span: lo });
+                    .then(|| IfExpressionLetSomeSub { if_span: lo.until(cond_span) });
 
                 self.sess.emit_err(IfExpressionMissingThenBlock {
                     if_span: lo,