Remove references to 'articles' instead of 'posts'

[johnbillion]

On the Settings -> Discussion screen, posts are referred to as "articles". The reason for this phrasing is to avoid "post" being used as a verb and a noun within the same sentence:

Allow people to post comments on new articles

Ref: https://core.trac.wordpress.org/ticket/22961#comment:9

This problem can be avoided by referring to submitting comments instead of posting comments:

Allow people to submit comments on new posts

There are a few related places where the phrase "article" is used instead of posts. These should all be replaced with "posts" for consistency.

[boonebgorges]

This always bothered me. +1 from me.

[desrosj]

The patch needs to be refreshed against trunk.

[angelagibson]

patch refresh;failed hunks fixed

[angelagibson]

New contributor here. I refreshed the patch and fixed the hunk failed errors in options-discussion.php and class-wp-xmlrpc-server.php

[johnbillion]

In 45401:

Administration: Replace references to "articles" with "posts" for greater consistency of terminology.

Props angelagibson

Fixes #38517

[SergeyBiryukov]

In 45443:

Administration: Replace one more reference to "articles" with "posts" for greater consistency of terminology.

See #38517.

[afercia]

In 45498:

Regenerate the REST API fixtures after [45443].

See #38517.

[joyously]

Now that this is done, I was having trouble explaining to a new user that those options apply to all post types with comment support, not just posts. (like Pages, Events, Portfolios, etc.)