Trivial grammar fix in const keyword docs
This PR makes a trivial fix to the wording of a sentence in the `const` keyword docs.
> `const` items looks remarkably similar to `static` items, [...]
Either this should be written as
> A `const` items looks remarkably similar to a `static` item, [...]
or "looks" should be changed to "look".
I have selected the smaller diff.
701bc03c52