Special-case lenses from makeLenses to link to field definition

[judah]

We had the following suggestion: currently, if you click on a lens generated by makeLenses, it goes to the original TemplateHaskell call $(makeLenses ...) (from Control.Lens.TH). That's technically correct, since that's where the lens is defined, but almost always what you really want is the original record field definition instead. For example, in

data Foo  = Foo { _bar :: Int }
$(makeLenses ''Foo)
...
... = ... bar ...

Clicking on bar in the last line should go to the original definition of _bar, rather than the call to makeLenses. The latter might not be close by the field, or it might be less convenient when there are many fields of a given record.

[robinp]

Didn't check deeply, but maybe the generates edges are useful for this - see #15 and https://kythe.io/docs/schema/#generates.

If you emit the generates edge between the right entities, then the Kythe indexer will magically make the connection.. kythe/kythe@f7614b1 might be some inspiration, but this cleanly needs more clarification. I remember there was a good readme in the Kythe repo (maybe https://www.kythe.io/docs/schema/indexing-generated-code.html?)