Map <bslash> to , (comma)

[gerardroche]

A lot of users map comma to <leader>, which means you can't use the comma key.

let mapleader=,

<bslash> is the default mapleader, so if we map <bslash> to comma then if a user sets comma as their mapleader they can use <bslash> to execute the default comma command (Repeat latest f, t, F or T in opposite [count] times). It's a win win.