fix clippy (#10659)

This pr fix clippy warnings in latest clippy version(1.72.0):

Unfortunally it's not easy to handle for [try
fold](https://rust-lang.github.io/rust-clippy/master/index.html#/manual_try_fold)
warning in `start command`

Refer to known issue:
> This lint doesn’t take into account whether a function does something
on the failure case, i.e., whether short-circuiting will affect
behavior. Refactoring to try_fold is not desirable in those cases.

That's the case for our code, which does something on the failure case.

So this pr is making a little refactor on `try_commands`.

crates/nu-command/src/date/parser.rs

@@ -98,7 +98,7 @@ fn timezone_offset_internal(
     };
     match s.len() {
         len if len >= 2 => &s[2..],
-        len if len == 0 => s,
+        0 => s,
         _ => return Err(ParseErrorKind::TooShort),
     };