Fix a spelling error in a comment

The comment was originally added in
https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4149962

Based on the commit message, I guess "those", not "these", was the
intended word.

Bug: 1403485
Change-Id: If3a72486b4d15a099ce1c2c4835d23a364c1e768
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4392153
Reviewed-by: Gavin Mak <gavinmak@google.com>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Junji Watanabe <jwata@google.com>
Commit-Queue: Wan-Teh Chang <wtc@google.com>

ninja.py

@@ -58,7 +58,7 @@ def main(args):
   # macOS's python sets CPATH, LIBRARY_PATH, SDKROOT implicitly.
   # https://openradar.appspot.com/radar?id=5608755232243712
   #
-  # Removing thoese environment variables to avoid affecting clang's behaviors.
+  # Removing those environment variables to avoid affecting clang's behaviors.
   if sys.platform == 'darwin':
     os.environ.pop("CPATH", None)
     os.environ.pop("LIBRARY_PATH", None)