Decodes exactly one escape sequence starting right after the
leading backslash (i.e. body[start] is the escape's first
character, not the backslash itself).
Parameters
body: string
start: number
Returns {next:number;text:string}
the decoded text and the
index right after the consumed escape.
Decodes exactly one escape sequence starting right after the leading backslash (i.e.
body[start]is the escape's first character, not the backslash itself).