cross-posting / xposting should be easier

[dd32]

On make.wordpress.org xposting to another P2 needs the specific syntax that O2 expects, which for a subdirectory-install like ours, is +make.wordpress.org/test/ including the full domain and the trailing slash.

It would be great if all of the following worked:

• +make.wordpress.org/example/
• +make.wordpress.org/example
• +example

Additionally, the xpost dropdown only works in the posts, and not comments (ie. When you type + in a post, it shows a selection list, but not in comments). This might be an upstream o2 issue.

[dd32]

I thought I'd already worked on this.. This was implemented via #6052 but apparently that might not be fully working.

[dd32]

In 11940:

O2: Cross-posting: Use more generic capability checks to hopefully allow cross-posting to work for non-editors, such as in comments.

See #6389, #6052.