Document new operators

[fhammerschmidt]

• ** for exponentiation, supports float, int and bigint
• % for remainder (in fact not modulo, see: https://bigmachine.io/career/mod-and-remainder-are-not-the-same), supports float, int and bigint
• ~~~ for bitwise NOT, supports int and bigint
• ||| for bitwise OR, supports int and bigint
• &&& for bitwise AND, supports int and bigint
• ^^^ for bitwise XOR, supports int and bigint
• << for left shift, supports int and bigint
• >> for right shift, supports int and bigint
• >>> for unsigned right shift, supports int only

Both add them to the syntax lookup and to their corresponding section (float, int, bigint) in https://rescript-lang.org/docs/manual/v12.0.0/primitive-types.