Rewrites window title according to config option "rewrite".
"rewrite" is an object where keys are regular expressions and values are
rewrite rules if the expression matches. Rules may contain references to
captures of the expression. Regex and replacement follow ECMA-script
rules. If no regex matches, the title is left unchanged.
example:
"sway/window": {
"rewrite": {
"(.*) - Mozilla Firefox": " $1",
"(.*) - zsh": " $1",
}
}