`<format>`: Investigate deriving `_Grapheme_Extend_ranges` from other tables

[StephanTLavavej]

For followup after we merge #3656.

S. B. Tam (@cpplearner):

• _Grapheme_Extend_ranges represents code points with the Unicode property Grapheme_Extend=Yes.
  • Characters in these ranges are escaped unless they immediately follow an unescaped character. ([format.string.escaped]/(2.2.1.2.2))
  • It would be more space efficient to reuse the existing data for Grapheme_Cluster_Break: Grapheme_Extend=Yes is Grapheme_Cluster_Break=Extend minus Emoji_Modifier=Yes, and Emoji_Modifier=Yes is just 1F3FB..1F3FF. I chose to define a new array for simplicity.

Charlie Barto (@barcharcraz):

This is a fairly decent amount of data. We should at least open an issue to derive these from the other tables.