.jshintrc

windows: continue looking at `%HOME%` for user config files with py3.8+

The `%HOME%` variable is explicitly called out in `hg help config` as a location
that is consulted when reading user files, but python stopped looking at it
when expanding '~' in py3.8+.[1]  Restore that old functionality by copying in
the old implementation (and simplifying it to just use bytes).  It could be
simplfied further, since only '~' is passed, but I'm not sure yet if we need to
make this a generic utility function on Windows.  There are other uses of
`os.path.expanduser()`, but this is the only case I know of that documents
`%HOME%` usage.

(The reason for removing it was that it typically isn't set, but it actually is
set in MSYS and PowerShell, and `%HOME%` and `%USERPROFILE%` are different in
MSYS.  I could be convinced to just replace all uses with this as a general
utility, so we don't have to think too hard about BC.)

[1] https://bugs.python.org/issue36264

Differential Revision: https://phab.mercurial-scm.org/D9559

{
    // 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)
}