Remove the `Commands: mappings` message in commit editor

[petobens]

Hi! I was wondering whether an option could be added to suppress the Commands: message within the commit editor? I actually modified the commit editor mappings and such message was not updated and, personally, i find it a bit distracting (one actually knows the mapings to commit/abort). Thanks in advance!

[CKolkey]

I tried it out and wasn't seeing any discrepancy between the custom mapping and the printed value - so I can't say thats an issue. But I'd accept a PR to make this configurable. Otherwise it's not something I feel very strongly about