[swift-evolution] [Proposal] Refining Identifier and Operator Symbology

[Ben Rimmington]

Re: <https://github.com/jsshapiro/swift-evolution/blob/unicode-id-op/proposals/NNNN-refining-identifiers-and-operators.md>

### Conventional Identifiers

`conventional-ident-head → [:Emoji:]`
will include the keycap base characters ('#', '*', ASCII digits).
<http://www.unicode.org/Public/emoji/4.0/emoji-data.txt>
<http://www.unicode.org/Public/emoji/4.0/emoji-sequences.txt>

Does the NFC format prevent emoji ZWJ sequences?
<http://www.unicode.org/Public/emoji/4.0/emoji-zwj-sequences.txt>

### Symbol Identifiers

You could include both blocks of mathematical operators.
* U+2200 ... U+22FF [:Block=Mathematical_Operators:]
* U+2A00 ... U+2AFF [:Block=Supplemental_Mathematical_Operators:]

-- Ben