DOC: Refine --reckless docstring on usage and wording

[adswa]

This is an attempt to fix #6039, in which a user's confusion over the
--reckless parameter could be traced to a lack of clarity
about the fact that this parameter is meant to be used at cloning.
Therefore, this change adds concrete examples and more refined wording
to the parameter docstring.
This change also removes a rather patronizing statement completely.

[codecov]

Codecov Report

Merging #6043 (5509539) into maint (588c2c8) will decrease coverage by 2.36%.
The diff coverage is 58.18%.

❗ Current head 5509539 differs from pull request most recent head a39c7dc. Consider uploading reports for the commit a39c7dc to get more accurate results

@@            Coverage Diff             @@
##            maint    #6043      +/-   ##
==========================================
- Coverage   90.27%   87.91%   -2.37%     
==========================================
  Files         312      312              
  Lines       42157    42189      +32     
==========================================
- Hits        38058    37091     -967     
- Misses       4099     5098     +999     

Impacted Files	Coverage Δ
datalad/config.py	96.70% <ø> (-0.01%)	⬇️
datalad/interface/common_opts.py	100.00% <ø> (ø)
datalad/customremotes/datalad.py	35.93% <12.50%> (-3.41%)	⬇️
datalad/cmdline/helpers.py	71.09% <14.28%> (-0.72%)	⬇️
datalad/__init__.py	81.21% <33.33%> (-5.38%)	⬇️
datalad/api.py	65.95% <33.33%> (-1.44%)	⬇️
datalad/customremotes/archives.py	62.71% <33.33%> (ø)
datalad/cmdline/main.py	74.57% <55.55%> (-1.74%)	⬇️
datalad/customremotes/base.py	83.26% <100.00%> (+0.13%)	⬆️
datalad/local/tests/test_subdataset.py	100.00% <100.00%> (ø)
... and 93 more

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[yarikoptic]

first I got confused with CI fails, but it is for "Branch" (not PR; and since PR is from a branch in this repo instead of a fork) so the base for this PR is a bit outdated (without fixes) maint.

[adswa]

first I got confused with CI fails, but it is for "Branch" (not PR; and since PR is from a branch in this repo instead of a fork) so the base for this PR is a bit outdated (without fixes) maint.

Will rebase, one second.

[mih]

Test failures are an intermittent fluke for codecov submission. No actual test failures.

[mih]

Let's see what the test will do. I left one more suggestion for an incremental improvement.

[mih]

Thx!