Escape extended ascii characters with backslashes

[jeparlefrancais]

Closes #104

Instead of escaping the characters with a unicode escape, which is available for Luau and Lua >= 5.3, use backslashes.

• [x] add entry to the changelog

[github-actions[bot]]

Coverage after merging escape-extended-ascii-with-backslash into main will be

89.36%

Coverage Report for Changed Files

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
src/generator
utils.rs	93.79%	100%	96.67%	93.46%	118, 125, 127, 18–19, 21, 23, 274–277, 49, 59, 69, 72, 81, 86