Missing wallet rpc methods in wallet-rpc.md

[MexicanTakeout]

A few methods I found missing in wallet-rpc.md while checking wallet_rpc_server.h from here ... to here

• freeze
• thaw
• frozen
• sweep_unmixable
• scan_tx
• exchange_multisig_keys
• set_log_level
• set_log_categories
• estimate_tx_size_and_weight

Let me know if you need a script showing these diffs.

[eversinc33]

sweep_unmixable is available in the documentation as sweep_dust (where the former is an alias for the latter).

Came here to open an issue about the same thing though.

[plowsof]

closed by #2083