change OS X to macOS (#41294)

* change OS X to macOS

<!--- Your description here -->

+label: docsite_pr

* Update all Mac OS X references to be macOS

* Drop extra Mac

test/integration/targets/tags/runme.sh

@@ -2,7 +2,7 @@
 
 set -eu
 
-# Using set -x for this test causes the Shippable console to stop receiving updates and the job to time out for OS X.
+# Using set -x for this test causes the Shippable console to stop receiving updates and the job to time out for macOS.
 # Once that issue is resolved the set -x option can be added above.
 
 # Run these using en_US.UTF-8 because list-tasks is a user output function and so it tailors its output to the

test/runner/injector/injector.py

@@ -120,7 +120,7 @@ def main():
         try:
             cwd = os.getcwd()
         except OSError as ex:
-            # some platforms, such as OS X, may not allow querying the working directory when using become to drop privileges
+            # some platforms, such as macOS, may not allow querying the working directory when using become to drop privileges
             if ex.errno != errno.EACCES:
                 raise
             if require_cwd: