Consider supporting fixity namespacing

[amesgen]

ormolu/src/Ormolu/Fixity/Parser.hs

Lines 48 to 57 in e3d67c8

	-- TODO Support fixity namespacing?
	-- https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0065-type-infix.rst
	--
	-- Note that currently, our fixity machinery does *not* do any namespacing:
	--
	-- - https://github.com/tweag/ormolu/pull/994#pullrequestreview-1396958951
	-- brought this up in the past
	--
	-- - https://github.com/tweag/ormolu/pull/1029#issue-1718217029
	-- has a concrete example (morley-prelude) where namespacing would matter

#1103 (comment)

[mrkkrp]

It looks like we should wait till fixity declarations without type or data keywords start to pertain exclusively to values. If my understanding is correct, then right now fixity declarations without type or data keyword still pertain to both values and types, so we would have to fallback to the current "common namespace" treatment even if we introduce the distinction.