doc: the typo train

Context

NB: This edition has been merged. The next edition of the typo train is !3289 (merged)

This MR is the current edition of the typo train, which aims lowering the overhead of small contributions to the documentation, such as: fixing typos or syntax issues, eliminating small incoherences, etc.

Feel free to add your contributions in the typo-doc branch!

This edition includes:

• a fix for #660 (closed)
• a warning about the importance of having a precise clock (requested by @pmetzger)
• a fix for a reward formula in the protocol
• some fixes for the new doc on RPC ACLs
• fixed links/cross-refs, improved sections structure, eliminated hardcoded constants/names

Manually testing the MR

Check that the contributions respect the criterion above and that they are right.

Checklist

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