Coinduction 1.22, for Rocq 9.2

• composition symbol (°) at level 40 to match other libs
• removed warnings and deprecated symbols for rocq 9.2
• formatting for `R notation
• helpers for PreOrder, Equivalence, Proper1, Proper2

this version needs rocq 9.2 ;
in case notation changes cause problems, coinduction.1.22 also compiles with rocq 9.2