Issue #1898422 by joelpittet, lokapujya, Salah Messaoud, stevector, Les Lim, pplantinga, jenlampton, drupalninja99, tlattimore, johannez | c4rl: Language.module - Convert theme_ functions to Twig.

Issue #2064639 by rahul.shinde, InternetDevels, martin107, longwave, jayeshanandani, connork, CarlHinton, vlad.n, superspring, andrei.dincu, stevepurkiss, jlindsey15, Salah Messaoud: Fixed Remove unused local variables from the node module.

Issue #2152201 by Salah Messaoud, Manuel Garcia, steveoliver, joelpittet, burgerboydaddy, katy5289, hussainweb, shanethehat, jenlampton, kpa, AnythonyR, EVIIILJ, kgoel, Cottser, dsdeiz, hanpersand: Convert theme_checkboxes() to Twig