Update tenses of doc comment summary lines (#4161)

This PR updates the tenses used by the summary line of doc comments to
match the [Rust API documentation
conventions](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#summary-sentence).

Specifically:

> The summary line should be written in third person singular present
indicative form. Basically, this means write ‘Returns’ instead of
‘Return’.

I'm sure there are plenty occurrences that I missed.

Release Notes:

- N/A

crates/language/src/syntax_map.rs

@@ -1296,7 +1296,7 @@ fn get_injections(
     }
 }
 
-/// Update the given list of included `ranges`, removing any ranges that intersect
+/// Updates the given list of included `ranges`, removing any ranges that intersect
 /// `removed_ranges`, and inserting the given `new_ranges`.
 ///
 /// Returns a new vector of ranges, and the range of the vector that was changed,