Add 😠 for mean ∘ skipmissing

[LilithHafner]

This comes from a recent gripe on slack. Somebody wants a shorter name for mean ∘ skipmissing and I figure this is a great opportunity to expand the user-base of this package.

While I'll admit :angry; is not ideal (:mean: would be better, were it a thing), I think this face looks a little mean: 😠, and I think the slight deviation is also appropriate as it reflects the semantic variation from traditional mean. If we used :mean:, folks might mistakenly think we were aliasing to Julia's mean.

Also, the motivation for this addition is a user's anger at not having a brief way of expressing mean ∘ skipmissing.

[Moelf]

we need @😠 for making everything skipmissing, just like @.

[theogf]

Sounds great could you just add it to the func_to_emojis Dict in WatchJuliaBurn.jl such that it also gets rendered in the README?

Just add a new line as:

:(mean ∘ skipmissing) = (:(😠),)

[LilithHafner]

Lovely! I didn't know that that dict could handle non-symbols on the LHS (e.g. sorting for the README & for equality in emojify).

[theogf]

Oh you're right... It might need some more hacking around. LGTM and I'll add some shady fix