Format tweaks

[aakoch]

Add blank lines and spaces to correct rendering of headers

[garemoko]

The blank lines shouldn't be needed #1034 fixes those issues in a different way.

The extra space on line 141 (How to Contribute) isn't covered by #1034. Good catch.

[garemoko]

In fact, #1034 missed fixing this file. I do thing the approach of #1034 fixing the anchor tags rather than adding a line space is better though.

Do you agree? If so, do you want to change your PR to follow that approach or shall I incorporate this file into #1034? It's a quick task for me to do, I just don't want to steal your thunder :-)

[garemoko]

I went ahead and rolled the anchor fixes for contributing.md into #1034.

I did not include the extra space on line 141 (How to Contribute) though, so if you remove the extra line breaks from this PR and just leave that extra space then we can merge it.

[andyjohnson]

Similar to #1035 , went with the larger merge first. Please re-submit working from the current merge if you can. Thanks!

[garemoko]

@andyjohnson I think this one can now be closed since #1039 includes this fix and more.