Issue #3084345 by solide-echt, gdejonghe, valthebald, aklump, mbovan, Sutharsan, wengerk: Fix usage of unsupported !title placeholder in Translation.php

(cherry picked from commit 6ca44f78)

Issue #3016420 by tim.plunkett, EclipseGc: Allow context definition annotations to specify constraints

Issue #3014949 by tim.plunkett: Deprecate 'context' on Block and Condition plugin annotations in favor of 'context_definitions'

Issue #2932462 by phenaproxima, japerry, tim.plunkett: Add EntityContextDefinition for the 80% use case

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 #1850080 by amateescu, dawehner, Xano, bojanz, martin107, Pancho, alexpott, tim.plunkett, icseh., stefank, Gábor Hojtsy, jhodgdon, tstoeckler: Entity type labels lack plurality, cannot generate UI text based on label if plural is needed

Issue #2576533 by alexpott, stefan.r, Wim Leers, dawehner, xjm, effulgentsia, catch: Rename SafeStringInterface to MarkupInterface and move related classes

Issue #2569069 by stefan.r, mr.baileys, alexpott, lauriii: Replace TranslationWrapper with TranslatableString and deprecate TranslationWrapper

Issue #1392754 by tss, justAChris, jhodgdon: Comply with new documentation standards for @file for namespaced class files

Issue #2349991 by fago, Xano, amateescu: Provide a trait for categorizing plugin managers and use it for conditions and actions

Issue #2339151 by EclipseGc, tim.plunkett, Gábor Hojtsy, effulgentsia: Conditions / context system does not allow for multiple configurable contexts, eg. language types

Issue #2038275 by tim.plunkett, mr.baileys, Sam Hermans: Convert hook_queue_info() to plugin system.

Issue #2299677 by er.pushpinderrana, gauravkhambhala | jhodgdon: Fix up annotation-related topics a bit.

Issue #2292889 by Berdir, tim.plunkett: Fixed ContextHandler does not expect ContextDefinitionInterface.

Issue #2281635 by fubhy, er.pushpinderrana, EclipseGc, blueminds, tim.plunkett: \Drupal\Core\Plugin\Context\Context should use a ContextDefinition class instead of arrays.

Issue #2216541 by jhodgdon, Gábor Hojtsy: Fill in topic/@defgroup docs for Internationalization overview.

Issue #2244447 by alexpott, sun, Berdir: Translation of low-level info/annotations leads to circular dependencies.

Issue #2079797 by ParisLiakos, Xano, amateescu, tim.plunkett: Provide a trait for $this->t() and $this->formatPlural().

Issue #2005716 by tim.plunkett, msonnabaum, dawehner, alexpott, effulgentsia: Promote EntityType to a domain object.

Issue #2077473 by dawehner, damiankloip, pwolanin: Replace local action plugin discovery with YamlDiscovery and handle routes with parameters.

Issue #2050919 by neclimdul, pwolanin, damiankloip, dawehner: Replace local task plugin discovery with YamlDiscovery.

Issue #2031473 by pwolanin, fubhy, dawehner, tim.plunkett: Convert menu local actions to plugins so that we can generate dynamic titles and paths.

Issue #1969970 by dawehner, jhodgdon, webchick, EclipseGc, tim.plunkett: Documentation for translatable plugin properties on annotations

Issue #1849752 by effulgentsia, Berdir, jibran, neclimdul: Abstract non-Drupal-specific parts of AnnotatedClassDiscovery into a Drupal\Component base class.

Issue #1849752 by effulgentsia, Berdir: Abstract non-Drupal-specific parts of AnnotatedClassDiscovery into a Drupal\Component base class.

- Patch #1683644 by chx, EclipseGc, tim.plunkett, aspilicious, xjm, dawehner, effulgentsia: use Annotations for plugin discovery.