Treat For each input work item like other run type keyword

[kylie-bee]

The keyword For each input work item out of the RPA.Robocorp.WorkItems library should use syntax highlighting similarly to Run keyword where the keyword to be ran is recognized as a keyword call. As this is a Robocorp-specific keyword, if we do not want to add that support directly into LSP, can we get some way to define such run keywords in the LSP config?

[fabioz]

Should be straightforward to add (and I think it should be done at the Robot Framework Language Server -- right now keywords are hard-coded there... ideally this should be in the libspec, but until then just hard-coding it there is straightforward).