chore: add suspicious_xor_user_as_pow clippy correctness lint (#973)

From the lint
[docs](https://rust-lang.github.io/rust-clippy/stable/index.html#suspicious_xor_used_as_pow):
> Warns for a Bitwise XOR (^) operator being probably confused as a
powering. It will not trigger if any of the numbers are not in decimal.
It’s most probably a typo and may lead to unexpected behaviours.

Cargo.toml

@@ -113,6 +113,7 @@ precedence_bits = "warn"
 rc_mutex = "warn"
 same_name_method = "warn"
 string_slice = "warn"
+suspicious_xor_used_as_pow = "warn"
 unused_result_ok = "warn"
 
 # == Style, readability == #