helptext: document share safe functionality in `hg help config -v`

If share safe functionality is enabled, we read `.hg/hgrc' of shared source.
13 jobs for topic/default/share-safe in 20 minutes and 54 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed checks-py2 #125769

00:04:32

passed checks-py3 #125770

00:04:01

passed rust-cargo-test-py2 #125771

00:02:19

passed rust-cargo-test-py3 #125772

00:02:34

passed rust-cargo-test-py3-dirstate-tree #125773

00:03:14

passed test-py2 #125774

00:20:35

failed test-py2-chg #125781

00:20:52

passed test-py2-pure #125776

00:20:31

passed test-py2-rust #125778

00:14:28

passed test-py3 #125775

00:12:40

passed test-py3-pure #125777

00:12:36

passed test-py3-rust #125779

00:13:07

passed test-py3-rust-dirstate-tree #125780

00:13:52

 
Name Stage Failure
failed
test-py2-chg Test
Failed test-chg.t: output changed
Failed test-config.t: output changed
Failed test-narrow-exchange.t#lfs-on: output changed
Failed test-share.t#safe: output changed
# Ran 854 tests, 92 skipped, 4 failed.
python hash seed: 433973110
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1