Revert "Merge pull request #2833 from mamhoff/new-bugfix-autocomplete"

This reverts commit 2450d284c50437d7a953488ff40bb8e40c8adf55, reversing
changes made to 489078bfcfce155bec58a4a544dc38b0e4e11cd1.
Fix pretty_text translation helper again, this time for real
remove unneeded topics-loading styles
switch to white spinner
remove some unused images
add spam hiding ability to lounge welcome
drop text from loading spinner
FIX: work around random encoding errors

(symptom is that site is blank see: https://meta.discourse.org/t/actionview-template-error-incompatible-character-encodings-utf-8-and-ascii-8bit/19970)
remove 1.9.3 from docs
Pending spec for Nokogiri fix
FEATURE: ninja op_likes sort for topic lists
Fix: CSS to reveal hidden or partially visible avatars on 2nd line

clear:left was added to an existing selector that match other elements that may no need it.

in case of a negative affect it should be moved to its own selector
.topic-map .links {
}
FIX: unlisted topics listed in activity stream
FIX: hide dangerous dev only site settings in production

(port/force hostname/queue jobs)
Merge pull request #2840 from lidlanca/patch-6

Fix: CSS to reveal hidden or partially visible avatars on 2nd line topic map
FIX: clicking on heading could insert a broken heading
amend previous fix
add more diagnostics to encoding issues
FIX: fix @mentions for usernames shorter than 2 characters

Super short usernames were enabled by
https://github.com/discourse/discourse/pull/2838
This is just a fix for @mentions
Update translations