Issue #2574981 by Manjit.Singh, dimaro, wengerk, darol100, izus, pguillard, vsujeetkumar, Himanshu5050, snehi, paulocs, rakesh.gectcr, jofitz, _utsavsharma, charginghawk, rajeshwari10, sdstyles, quietone, benjifisher, marcusvsouza, LoMo, joelpittet, justAChris, cilefen, YesCT, mradcliffe, spitzialist, annajl, jhodgdon, catch, alexpott, Sabbi0612, kattekrab, Mile23, antojose, leanderl, rodrigoac: Fix grammar ("an URL" should be "a URL") and consistent use of URL (not "url" / "Url") in documentation only

Issue #1472946 by gnuget, andypost, mmrares, sidharthap, kiamlaluno, Himanshu5050, dineshkumares, amit.drupal: Remove usages of deprecated function drupal_realpath() throughout core functions

Issue #2643250 by Chi, emma.maria, talhaparacha, Himanshu5050: Bartik: replace the field--name-field-user-picture class with field--name-user-picture in the CSS

Issue #2606376 by rakesh.gectcr, Himanshu5050, sdstyles, dawehner, nicrodgers: mark \Drupal::l()  as deprecated

Issue #2599190 by chegor, rakesh.gectcr, sdstyles, aneeshthankachan, anil280988, Himanshu5050, jhodgdon: Update upgrading procedure describing in UPGRADE.txt

Issue #2599442 by jhodgdon, heykarthikwithu, Himanshu5050, eojthebrave, metzlerd: Document common form/render element properties