Hygiene: More LESS cleanup in ext.echo.overlays.less
Hygiene: More LESS cleanup in ext.echo.overlays.less

Change-Id: I2d2daad00a11a156dc0ac693ea99322c9470cc6f

wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo