Typo (add codeface) (#31920)

Update index.md

files/en-us/web/javascript/guide/expressions_and_operators/index.md

@@ -184,7 +184,7 @@ console.log(f(0, x = f(), 0));
 The evaluation result matches the expression to the right of the `=` sign in the
 "Meaning" column of the table above. That means that `x = f()` evaluates into
 whatever `f()`'s result is, `x += f()` evaluates into the resulting sum `x + f()`,
-`x **= f()` evaluates into the resulting power `x ** y`, and so on.
+`x **= f() evaluates into the resulting power x ** f(), and so on.
 
 In the case of logical assignments, `x &&= f()`,
 `x ||= f()`, and `x ??= f()`, the return value is that of the