I did not want to put this in the ongoing review topic of the proposal. I'm leaving it here because I don't know of a better place.
Problem: Some digit character groups match number-like grapheme clusters.
// this matches: try /[1-2]/.wholeMatch(in: "1️⃣") // still matches: try /[1-2]/.asciiOnlyDigits().wholeMatch(in: "1️⃣") // does not match: try //.wholeMatch(in: "1️⃣")
Above described behavior seems inconsistent and difficult to predict. Shouldn't
 be identical? Should they match anything outside of ascii?
Note: is U+0031 (ascii digit 1) U+FE0F (VARIATION SELECTOR-16) U+20E3 (COMBINING ENCLOSING KEYCAP)
Same is true for 1︎⃣: U+0031 (ascii digit 1) U+FE0E (VARIATION SELECTOR-15) U+20E3 (COMBINING ENCLOSING KEYCAP)