Cross-project matches should copy the translation author

[SergeyBiryukov]

When double-checking the strings approved by someone else, I often check out the translation author to see if it's my own string or if I've already checked and corrected it in the past.

If the author is an experienced contributor, I just take a quick glance at the string to make sure there are no typos.

If the author is a new contributor, I spend some more time to check the context and improve the wording.

If the author is me, I know I've already checked this string before.

But cross-project matches currently don't copy over the translation author, which makes the review harder.

For example, ​"Akismet cleared this comment" string in dev project has an author, but ​the same string in stable project doesn't have it.

[SergeyBiryukov]

Related: #1411

[ocean90]

Cross-project matching is a feature from GlotPress. Please report this on ​https://glotpress.trac.wordpress.org.

[SergeyBiryukov]

Follow-up: ​#glotpress521.