Move SelectionRange and SelectionRangeKind to types

[aeschli]

SelectionRange and SelectionRangeKind should go into types

[dbaeumer]

I have to say that I don't like the type package anymore. Makes my live unnecessary complicated :-)

[rcjsuen]

I use this package exclusively to separate out the language service logic and the language server logic. So I like it anyway. :P

[dbaeumer]

I can move them if the selection range becomes stable. The type package has no proposed support :-(.

[dbaeumer]

This got magically done :-)