docs: Demonstrate CLI API over running module as script

[matthewfeickert]

• As installation creates the executables 'bin/scikit-hep-testdata' and 'bin/skhep-testdata', demonstrate these in the README rather than running the module as a script with '-m'.
  • c.f. https://docs.python.org/3/using/cmdline.html#cmdoption-m

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.51%. Comparing base (8c71761) to head (d0796ab).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #195   +/-   ##
=======================================
  Coverage   72.51%   72.51%           
=======================================
  Files           4        4           
  Lines         131      131           
=======================================
  Hits           95       95           
  Misses         36       36           

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[matthewfeickert]

cc @henryiii for review as he was the last to touch this segment of the README and added the CLI options in PR #51.

[APN-Pucky]

Suggested change

	```
	```bash

[matthewfeickert]

Bash syntax highlighting on GitHub looks the same as no syntax highlighting on GitHub if you aren't using explicit Bash commands. I would normally suggest console, as that's more correct as people will be executing these in shells regardless of shell type, but that does change the syntax highlighting in a way that just converts all of it to a new color, which isn't very useful.

Is there an advantage to selecting bash here? If no, should we change Scikit-HEP style recommendations?

[APN-Pucky]

Suggested change

	```
	```bash

[APN-Pucky]

Suggested change

	```
	```bash

[eduardo-rodrigues]

The changes seem good to me.