misc: fix common typos

[paulirish]

a few of these were discovered by a downstream tool. (to be clear i don't care about these changes, but i'd rather not have that tool complain every time i roll there :)

nearly all changes are @returns to @return.

but then there's three typos as well: commiting, i.e (missing a second period), releated

[brendankenny]

nearly all changes are @returns to @return.

vscode has been autosuggesting this recently when I write /**[tab] on top of a function and I haven't been able to figure out how to change it :/

[patrickhulce]

LGTM overzealous google3 bot :)