Issue 2408: [documentation] fix default ledger manager and Qw value in documentation

[lifepuzzlefun]

fix #2408

1. fix documentation concept part about default ledger manager.
2. fix documentation protocol part about missing Qw value.

Descriptions of the changes in this PR:

Motivation

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Changes

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Master Issue: #

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[eolivelli]

LGTM

Thank you