Issue #2491155 by mikeburrelljr, Mac_Weber, opdavies: Update drupal.org and kernel.org URLs in core modules (Follow-up to 2489912)

Issue #2347465 by tim.plunkett, dawehner, cilefen: Convert all instances of #type link/links to convert to use routes.

Issue #2343759 by pwolanin, larowlan, dawehner, tim.plunkett, effulgentsia, xjm, Wim Leers: Provide an API function to replace url()/l() for external urls.