Rename: getcolptr -> colptrs

[tkf]

As @ViralBShah suggested in #32953 (comment), it makes sense to drop get prefix from getcolptr(::SparseMatrixCSC). To be compatible with rowvals and nonzeros, it may be better to use colptrs?

Also, maybe it's better to remove getrowval and getnzval (or deprecate them, if we want to be extra careful) as they are just aliases of rowvals and nonzeros?

See also #33039

[ViralBShah]

Agree with all the suggestions.

[tkf]

Good to know! Can #33039 and maybe also #33037 (edit: it's merged) go first? This patch is literally just sed -E -i 's/\bgetcolptr\b/colptrs/g' so re-doing this is pretty easy. On the other hand, the other patches are more delicate.

[tkf]

There are other suggestions in #25118. coloffsets makes sense to me.

[tkf]

Let's do this in #33054.