Improve shader docs

I think it would be easier to search for a question if the “issues” section was grouped and links for each topic made that would point to expanded explanation. It’s too tiring to read thru the whole list to find the one issue of concern. Also, this linkage should be replicated in the bookmarks bar of the pdf window(ie. on the left side).

Same goes for gl specs. Have a look at dx9 docs or c++ standard pdf how it’s properly done. Thanks.