minor corrections - whitespace and links

[duffee]

Also added comments highlighting TODOs in Indexing asking for more content.

(fixed irritating git config mistake to track upstream not origin )

I see that PDL::Index needs to be regenerated by utils/scantree.pl before the next release to pick of the move of PDL::MATLAB to PDL::Guides::Migration::MATLAB. I tried on my machine, but got errors and when I did produce an Index.pod, I saw some parsing errors that I couldn't determine the cause of, like this diff fragment

-L<PDL::Parallel::threads::SIMD> - launch and synchronize Single-Instruction-Multiple-Dataset code
+L<PDL::Parallel::threads::SIMD> - launch and synchronize
+

where it just truncates the item. It also includes way too many modules in the Index, so I'll pretend I didn't see that and move on. ;)

[coveralls]

coverage: 70.07%. remained the same — duffee:POD-Graphics-Internals into PDLPorters:master

[mohawk2]

Thank you for this! Please could you make a couple of tweaks?

[mohawk2]

I've squashed this for tidiness, thank you for your diligent work in making things better!