Updated mediawiki/extensions
Project: mediawiki/extensions/Echo  e673ea6763fa06048311a55dacc3792cd4dcff94

ext.echo.special: Move #firstHeading styling from JS to CSS

Also some code cleanup in the part about converting subtitle links
into header icons.

Change-Id: I25eacb9c512fd6883a65df3af97608749b53b228