Issue #2857857 by vegantriathlete, Jo Fitzgerald, snehi, plach, xjm, Skabbkladden: Check use of "it's" in core to ensure proper use

Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2107243 by amateescu, jibran, larowlan, Xano: Decouple entity reference selection plugins from field definitions

Issue #2290259 by g3r4, er.pushpinderrana, joshi.rohit100, amitgoyal: Make developer docs for entity reference selection plugins more discoverable