Re: fixing typo in comment for restriction_is_or_clause

On 2022-Oct-25, Richard Guo wrote:

> Agree with your point.  Do you think we can further make the one-line
> function a macro or an inline function in the .h file?

We can, but should we?

> I think this function is called quite frequently during planning, so
> maybe doing that would bring a little bit of efficiency.

You'd need to measure it and show some gains.