Meta tracking issue for release notes PRs

To hopefully make it easier to find previous release notes PRs (due to github PR search funny business). Only goes back to 1.50 for the time being.

• 1.91 #147010
• 1.90 #145730
• 1.89 #144509
• 1.88 #142828
• 1.87: #140133
• 1.86: #138795 (PR: #139002)
• 1.85: #135797
• 1.84.1: #136256
• 1.84: #134568
• 1.83: #133320
• 1.82: #131137
• 1.81: #128523
• 1.80.1:
  • stable: #128635
  • master: #129930
• 1.80: #127083
• 1.79: #125470
• 1.78: #123248
• 1.77.2:
  • stable: #123681
  • master: #123683
• 1.77.1:
  • stable: #123105 (yes, indeed)
  • master: #123187
• 1.77: #121862
• 1.76: #120004
• 1.75: #118729
• 1.74.1:
  • stable: #118607
  • master: #119068
• 1.74: #116778
• 1.73: #116083
• 1.72.1:
  • stable: #115787
  • master: #115978
• 1.72: #114563
• 1.71.1:
  • stable: #114284
  • master: #115997
• 1.71: #113138
• 1.70: #111006
• 1.69: #110033
• 1.68.2:
  • stable: #109644
  • master: #109658
• 1.68.1:
  • stable: #109335
  • master: #109658
• 1.68: #108041
• 1.67.1:
  • stable: #107743
  • master: #107861
• 1.67: #107142
• 1.66.1:
  • stable: #106685
  • master: #106687
• 1.66: #104405
• 1.65: #102659
• 1.64: #101093
• 1.63: #99524
• 1.62.1:
  • stable: #99299
  • master: #99524 (yes, indeed)
• 1.62: #97454
• 1.61: #96539
• 1.60: #94817
• 1.59: #93639
• 1.58.1:
  • stable №1: #93071
  • stable №2: #93110
  • master: #93136
• 1.58: #92055
• 1.57: #90832
• 1.56.1:
  • stable: #90460
  • master: #90462
• 1.56: #88893
• 1.55: #88170
• 1.54: #86696
• 1.53: #85541
• 1.52.1:
  • stable: #85097
  • master: #85404
• 1.52: #84183
• 1.51: #81917
• 1.50: #80812

Also including some search keywords to make this issue easier to find: relnotes, release notes

This issue is a historical index of Rust release-notes pull requests and does not name a source file, test, or entry point. Start by checking whether a release-notes PR is missing from the list; done would mean adding or correcting the relevant version and PR link.