Display content of blog index or blog-section index

[froboy]

Fixes #1787.

I needed this for my project and saw the issue open. Currently Blog Section pages don't have a h1 either, so this adds the title of the section as well.

[froboy]

@chalin I took a quick stab at this. The content and title will be shown above Blog Sections.

From our site, as an example:

[froboy]

Not quite... this displays the content on section pages, but duplicates it on blog items. Working on a fix.

[froboy]

{{ if .IsSection }} fixed that up.

[chalin]

Closed in favor of:

• #2157