fix typo

Co-authored-by: bjorn3 <17426603+bjorn3@users.noreply.github.com>

Author: squell

src/defaults/mod.rs

@@ -63,7 +63,7 @@ defaults! {
 /// passwd_timeout and timestamp_timeout.
 fn fractional_minutes(input: &str) -> Option<i64> {
     if let Some((integral, fractional)) = input.split_once('.') {
-        // - 'input' is maximally 18 chacters, making fractional.len() at most 17;
+        // - 'input' is maximally 18 characters, making fractional.len() at most 17;
         //   1e17 < 2**63, so the definition of 'shift' will not overflow.
         // - for the same reason, if both parses in the definition of 'seconds' succeed,
         //   we will have constructed an integer < 1e17.