Restore 'Search Engines Discouraged' text to the Dashboard

[mako09]

Help text at Settings -> Reading -> Help -> Search Engine Visiblity has the 2nd paragraph,

When this setting is in effect, a reminder is shown in the Right Now box of the Dashboard that says,
“Search Engines Discouraged,” to remind you that your site is not being crawled.

These words are not found in Dashboad because dashboard design has been changed[26144].

It seems that the 2nd paragraph of this help text should be removed.

[helen]

Or maybe we need to add the line back to Site Content / Right Now?

[nacin]

Hm. Yeah, where'd that go?

[JustinSainton]

26431.2.diff​ restores the previous text into the Site Content box and changes the help text (s/Right Now/Site Content).

Restores two filters that went missing as well and will need documentation.

[JustinSainton]

26431.3.diff​ is a first pass at inline docs.

[nacin]

In 26700:

Restore "Search Engines Discouraged" to the dashboard.

props JustinSainton.
fixes #26431.

[nacin]

See [26697] for the rename of the widget.