Fix Typos in Code and Documentation

[leopardracer]

Description:
This pull request addresses several typographical errors in both the codebase and documentation. The changes include:

1. Code Corrections:

   • Corrected spelling of "descendants" in consensus/src/extension/election.rs.
   • Fixed "received" spelling in multiple locations within consensus/src/terminator.rs.

2. Documentation Updates:

   • Corrected "retrieving" spelling in docs/src/aleph_bft_api.md.
   • Fixed "broadcast" spelling in docs/src/how_alephbft_does_it.md.

3. Log Message Fix:

   • Corrected log message spelling in examples/blockchain/src/network.rs.

These changes improve the readability and professionalism of the code and documentation.

[github-actions]

Please make sure the following happened

• Appropriate tests created
• Infrastructure updated accordingly
• Updated existing documentation
• New documentation created
• Version bumped if breaking changes