Resolve overflow-clip naming collision issue

[reinink]

Resolves #4622

With overflow: clip becoming more widely supported by browsers, we are running into a naming collision with the existing overflow-clip utility, which sets text-overflow: clip.

This PR renames the existing text-overflow utilities as following:

Old Class	New Class
overflow-ellipsis	text-ellipsis
overflow-clip	text-clip

We considered using ellipsis and clip for these utilities, but using the prefix makes these utilities more resilient to new values being supported in the future. For example, Firefox already supports values like text-overflow: "-".

Renaming overflow-clip to text-clip is a breaking change, but I expect the impact will be very low, since text-overflow: clip is the browser default, and there are very few reasons to actually use that class.

We are not removing the existing overflow-ellipsis utility because that would be an unnecessary breaking change, but it is now considered deprecated, and will no longer be documented.

With the overflow-clip class now available, we've also added the new overflow: clip utilities:

Class	CSS
overflow-clip	overflow: clip
overflow-x-clip	overflow-x: clip
overflow-y-clip	overflow-y: clip