minor #20330 [Messenger] Replace the tables by definition lists (javiereguiluz)

This PR was squashed before being merged into the 6.4 branch.

Discussion
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[Messenger] Replace the tables by definition lists

As a general rule, we should never use tables for list of options with long descriptions. The tables look ugly and the option names are unreadable:

![image](https://github.com/user-attachments/assets/13e70024-5763-455e-bb18-25c590618862)

In this PR, I propose to replace all tables with definition lists, which we use in all the other docs.

Commits
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d0ed00f [Messenger] Replace the tables by definition lists

Author: javiereguiluz