let statements _within_ match patterns now need parens. adding sections to palette options. etc.

src/parser.ts

@@ -366,7 +366,7 @@ export class Parser {
         this.expect('equals');
         const value = this.parseExpression();
         this.expect('semicolon');
-        const body = this.parseExpressionNoMatch();
+        const body = this.parseExpression();
 
         return { kind: 'let', name, value, body, ...this.getPos(nameToken) };
     }