Backslash reform

• Bracketing constructs

  • \x[263a] \x{263a} \x(263a) \x<263a>

• General rule: \X is the negation of \x

• Obsoleted: \L \U \Q \p \P \a \A \Z \z \G

• Changed: \n \r \c \C \E \F \N \R \T \X

• New: \h \v