Changes imported from Abseil "staging" branch:

  - cdcf33b6176a51b6b9bcdf1032b4aa407a9a6990 Clarify that "0" without a suffix parses to ZeroDuration(... by Abseil Team <absl-team@google.com>
  - 65c8997d5a3a4cff63f1dc8a72dcee89c456a17b spelling 'available' by Abseil Team <absl-team@google.com>
  - 1a2b51427c38d471a3f2b8806f015d1598877559 Clean up a comment by Abseil Team <absl-team@google.com>
  - ea1ae153fff759a60fbf946f2865f14253e21289 Fix typo in string_view comments. by Abseil Team <absl-team@google.com>
  - 94d7e6d9e9e379e352aa3cc5e37ac4ffd81db234 Replace x64_windows_msvc with x64_windows (bazel default)... by Xiaoyi Zhang <zhangxy@google.com>

GitOrigin-RevId: cdcf33b6176a51b6b9bcdf1032b4aa407a9a6990
Change-Id: I3ccdcf1b8c5c08997e68cb1f336b02f003a3a72d