Using h specifier might cause overlap with hour's specifier

[xsoh]

As @mj1856 suggested on this Add moment-hijri to plugins #164 pull, that the h specifier might cause overlap with hour's specifier.
For that it should be change to another specifier. The better specifier is to use i instead. That is because it represent Islamic Calendar and also Hijri has two I`s 👀

This change will make a big difference for the tool usage, for that I suggest to be the v2.0 of moment-hijri.