[Clarity] Minor Docs

[G8XSU]

• In ChannelManager we have to wait for initial sync to complete. (clarity)
• Monitor Updates need to be persisted in sequential fashion (specially when async) (clarity)

[TheBlueMatt]

Slipping to 114, not sure why this has a 113 tag if it wasnt assigned to anyone.

[dunxen]

Are we moving this to 115? I can take it if I know where we should be clarifying the above to make it obvious to the user.

[TheBlueMatt]

Yea, I'm honestly not sure what the first one refers to. The second is kinda implied by docs today, but we definitely need to include it when we rewrite docs for fully-async monitor updates. Will note it in #1684.

@G8XSU can you suggest something concrete for the first bullet? Either way 114 doesnt need to wait on this.

[G8XSU]

I think both points are based on feedback from Lexe,
and first bullet means, ChannelManager and monitors need to be fully synced before client starts using channel-manager api's (including block-sync).