syncthing 0.10.11

Closes #34790.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
syncthing: update 0.10.11 bottle.
icdiff 1.1.2 (new formula)

Closes #34758.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
icdiff: remove unnecessary version, improve test.

Let's not use temporary files that will stick around afterwards.
Merge remote-tracking branch 'upstream/master'