upgrade: rename finddeficiences() to find_format_upgrades() It was not obvious what does deficieny means and every format upgrade can't be a deficiency. There are some format upgrades like compression levels, share-safe which can't be understood at deficiencies. A change can be an upgrade or downgrade, however this `finddeficiences()` only used to find upgrades. This patch renames the function and related variables to make things more clearer. The ui message also got improved which is a good thing. Next patch will rename deficiency in general across the upgrade code. Differential Revision: https://phab.mercurial-scm.org/D9582

{
    // 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)
}