doc: add Neomake help tag (#1237)
doc: add Neomake help tag (#1237)

Linking to `neomake.txt` does not work by default?! ('.' missing in
'iskeyword').
euclio/neomake,euclio/neomake,nerdrew/neomake,codeinabox/neomake,neomake/neomake,bonds/neomake,neomake/neomake,nerdrew/neomake,bonds/neomake