Docs: Typo and clarifications

This merge request does 3 quite unrelated things, one per commit. If granularity is not the expected one, either too coarse-grained (3 separate MRs would be more suitable) or too fine-grained (only 1 commit would do the job), please do not hesitate to mention it.

What

Correct a few typos and wrong paths met during my reading of the docs, as well as detailing a bit the results of the commands used to observe the chain while running in a sandbox.

Why

About typos and wrong paths, I do not think I really have to justify corrections. For the more detailed output of the rpc get ... commands on sandboxed networks, I was quite surprised to not get a result similar enough to the one presented in the tutorial, hence I expect it to be less disturbing for next newcomers with this presentation.

How

Only doc modification, no functional impact.

Manually testing the MR

Only doc modification, no functional impact.

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR