Function to get Unicode code point notation like `U+0061` about julia

[Paalon]

Which is better?

• Implement in julia/base/char.jl
• Implement in julia/stdlib/Unicode/src/Unicode.jl

And if isoverlong(c) is true, how should we treat it?
And what function name should we use? codepoint is used for the UInt32 number, and the Unicode official document calls it only "Unicode code point" in the section of notational conventions. How about codepointnotation or codepointconvention? Is it a bit long?

[Paalon]

Overlong codes should be decoded so what we need is to implement as show does:

function codepoint_notation(c::AbstractChar)
    u = Base.isoverlong(c) ? Base.decode_overlong(c) : codepoint(c)
    "U+" * uppercase(string(u, base=16, pad=4))
end