diff: when looking for diff configs, support a configurable prefix
In a future commit, I want to make it possible to have the diff options pulled
from (as an example) `commands.commit.interactive.ignorews`; previously we only
supported this for customizable sections (so this would have needed a
`commit-interactive` section and been named `commit-interactive.ignorews`, which
felt a bit weird.
Differential Revision: https://phab.mercurial-scm.org/D5833
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}