Move impl's into macro for macro-generated keyword types
Three keyword types are created through a macro but have some of their
impl's handled elsewhere. Since all impl's are the same, this commit
moves them into the macro to have them auto generated, for more concise
code.
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- [X] `./mach build -d` does not report any errors
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- [X] These changes fix#16604 (github issue number if applicable).
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