Issue #3268818 by ravi.shankar, quietone: Fix class comment doc blocks in non tests 'Drupal.Commenting.DocComment.ShortSingleLine'

Issue #2851394 by GoZ, hgunicamp, oknate, jungle, wolffereast, tameeshb, mmatsoo, ridhimaabrol24, jofitz, swarad07, tanc, shaktik, dimaro, shashikant_chauhan, MerryHamster, quietone, nitesh624, martin_q, boaloysius, gaurav.kapoor, nitvirus, ankithashetty, Munavijayalakshmi, kostyashupenko, leolando.tan, amit.drupal, ravi.shankar, akashkrishnan01, Swapnil_Kotwal, Saviktor, mrinalini9, anmolgoyal74, Venkatesh Rajan.J, shimpy, lomasr, Dinesh18, shubham.prakash, mahtab_alam, markdorison, cilefen, longwave, bleen, xjm, alexpott, gmaltoni: Fix grammar 'a' to 'an' when necessary

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

Issue #2599524 by blackra, krknth, jhodgdon, rhett.prichard: Fixing order of documentation sections for /core/lib/Drupal

Issue #2165475 by damiankloip, dawehner, martin107, tim.plunkett, jibran, xjm, Jalandhar: Provide a generic class resolver.