lexer: Fix bug that did not check the second character of identifiers. This also fixes one-character identifiers not being properly detected.

src/lexer.rs

@@ -124,7 +124,7 @@ impl<'t> Lexer<'t> {
             '|' => self.then().emit(TokenKind::Bar),
             '}' => self.then().emit(TokenKind::CloseCurly),
             c if c.is_numeric() => self.number::<DEFAULT_BASE>(),
-            &c if is_xid_start(c) => self.then().identifier(),
+            &c if is_xid_start(c) => self.identifier(),
             c => todo!("Unrecognized character: {c}"),
         }
     }