Issue #2217731 by crowdcg, lauriii, davidhernandez, aczietlow, jjcarrion, mortendk, karolus, pakmanlh, LewisNyman, aboros, joshua.boltz: Move field classes out of preprocess and into templates

Issue #1623574 by droplet, cilefen, cesarmiquel, patrickfgoddard, sun, zaporylie, er.pushpinderrana, stevecowie, mbroere: Fixed Remove trailing space from form element labels and field labels (HTML nbsp).

Issue #2229435 by lauriii, joelpittet, Rade: Clean up the way attributes are printed in field.html.twig.

Issue #2298923 by mparker17, er.pushpinderrana: Fixed Bartik's field--taxonomy-term-reference.html.twig doesn't output content_attributes, has out-of-date documentation.

Issue #2301599 by Cottser, mparker17: Fixed Regression: Bartik's field--taxonomy-term-reference.html.twig doesn't properly output label attributes.

Issue #2227601 by mparker17, cs_shadow, swentel, lanchez, mgifford: Added a "Visually-hidden" field label formatter.

Issue #2227869 by joelpittet: Remove magic printing from Attribute class to make Twig 'without' filter work for attributes.

Issue #2226185 by galooph, filijonka, Cottser: Remove @ingroup themeable from core theme Twig template docblocks.

Issue #1987398 by Nigel_S, Tim Bozeman, InternetDevels, adsw12, joelpittet, Cottser, mdrummond, dsayswhat, jerdavis, rteijeiro, LewisNyman, Rumato, gnuget: Field.module - Convert theme_ functions to Twig.