Move `symFromType` and `symNodeFromType` from `sem`, and `isSelf` and
`makeTypeDesc` from `concepts` into `semdata`.
`makeTypeDesc` was moved out from semdata [when the `concepts` module
was
added](6278b5d89a),
so its old position might have been intended. If not, `isSelf` can also
go in `ast`.
* Add testcase
This tries to use a concept with a doc comment which currently leads to a segfault
* Ignore nil nodes which happen when there are doc comments in new style concept
This was done instead of semming the comments since `semConceptDecl` says it only supports lists of actual statements
* Go with alternative fix: Sem comments but ignore them
Since `nil` could mean anything it is best to not silently ignore it (In case another nil problem happens in future
Also fix test case so it isn't an infinite loop
* refactoring in preparation for better, simpler name mangling that works with IC flawlessly
* use new disamb field
* see if this makes tests green
* make tests green again
* fixes#15210 [backport:1.2]
* make tests green
* make ordinal work
* makes Swapable test compile
* make Indexable example work
* concepts: 'self' is now 'Self'
* concepts: make Dictionary example compile
* document the new concept implementation
* concepts: make typeDesc work properly
* concepts: allow documentation comments (d'oh)
