UX: Report the sibling name in create-sibling-github's results record

[adswa]

Here's my attempt at reporting a sibling name when a GitHub sibling is created, as desired in #5711. Its not a separate key in the result, but merely added into the message, but I found that it looked quite crowded when I rendered several messages.
Here is the current look:

[bpoldrack]

LGTM.

Just would like to see a different title since it appears in the changelog. THis is not about result rendering. You just changed the message in the possibly-to-be-rendered result record.

[adswa]

better like this, @bpoldrack?

[codecov]

Codecov Report

Merging #5744 (858f088) into master (f5b6db0) will decrease coverage by 2.57%.
The diff coverage is 100.00%.

❗ Current head 858f088 differs from pull request most recent head be4b3c1. Consider uploading reports for the commit be4b3c1 to get more accurate results

@@            Coverage Diff             @@
##           master    #5744      +/-   ##
==========================================
- Coverage   90.63%   88.06%   -2.58%     
==========================================
  Files         308      305       -3     
  Lines       42181    42163      -18     
==========================================
- Hits        38231    37130    -1101     
- Misses       3950     5033    +1083     

Impacted Files	Coverage Δ
datalad/distribution/create_sibling_github.py	93.44% <100.00%> (ø)
datalad/plugin/wtf.py	0.00% <0.00%> (-100.00%)	⬇️
datalad/plugin/addurls.py	0.00% <0.00%> (-100.00%)	⬇️
datalad/plugin/no_annex.py	0.00% <0.00%> (-100.00%)	⬇️
datalad/plugin/add_readme.py	0.00% <0.00%> (-100.00%)	⬇️
datalad/plugin/check_dates.py	0.00% <0.00%> (-100.00%)	⬇️
datalad/support/tests/utils.py	0.00% <0.00%> (-100.00%)	⬇️
datalad/plugin/export_archive.py	0.00% <0.00%> (-100.00%)	⬇️
datalad/plugin/export_to_figshare.py	0.00% <0.00%> (-100.00%)	⬇️
datalad/metadata/extractors/tests/test_audio.py	19.35% <0.00%> (-80.65%)	⬇️
... and 95 more

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[mih]

Cool, thx!