Update Swift.

[gonsolo]

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[e3b0c442]

There is some disparity here with the documentation, the difference it appears being that the documentation focuses on those keywords that can't be used as identifiers (so the strict keywords).

I'll admit that I recompiled this long enough ago that I'm not 100% certain which standard I tried to hold to. Looking at Rust (which currently, if not previously, makes this distinction) does not clear things up, as I have the weak keywords union and 'static but not macro_rules, safe, or raw.

I'm going to take a little time to check some other languages on this list, especially ones where the lever is Open Source (thank you for linking to the Swift source code) and see if I can unmuddy this picture before accepting the PR, as this is quite a fundamental change to how Swift keywords had been tabulated previously.