fmt: improve str{f,p}time compatibility

This adds a whole bunch of conversion specifiers from reading
`man strftime` on my system (GNU libc).

I originally didn't add most of these because they bloat the size of
`BrokenDownTime` and many of them seem a little dubious. But a few folks
have filed issues about compatibility. Given the `strtime` API is
already a complete clusterfuck, it probably makes sense to just match
existing practice as much as we can.

One conversion specifier I intend to add but haven't yet is `%V` for the
ISO 8601 week number. It is conspicuously absent here since `%V` is
currently used for IANA time zone identifiers. That will change in
`jiff 0.2`, which will make room for `%V` to be the ISO 8601 week
number.

Ref #139, Ref #147

CHANGELOG.md

@@ -26,6 +26,14 @@ result in an error. This change was made to improve compatibility with other
 time zone identifiers in `jiff 0.1`, but using them for parsing or formatting
 will result in a WARN-level deprecation message.
 
+Enhancements:
+
+* [#147](https://github.com/BurntSushi/jiff/issues/147):
+Adds a number of new conversion specifiers to Jiff's `strftime` and
+`strptime` APIs. Specifically, `%C`, `%G`, `%g`, `%j`, `%k`, `%l`, `%n`, `%R`,
+`%s`, `%t`, `%U`, `%u`, `%W`, `%w`. Their behavior should match the
+corresponding specifiers in GNU libc.
+
 
 0.1.24 (2025-01-16)
 ===================

src/civil/date.rs

@@ -563,10 +563,8 @@ impl Date {
     /// ```
     #[inline]
     pub fn day_of_year(self) -> i16 {
-        type DayOfYear = ri16<1, 366>;
-
         let days = C(1) + self.since_days_ranged(self.first_of_year());
-        DayOfYear::rfrom(days).get()
+        t::DayOfYear::rfrom(days).get()
     }
 
     /// Returns the ordinal day of the year that this date resides in, but
@@ -3669,9 +3667,7 @@ fn month_add_overflowing(
 }
 
 fn day_of_year(year: Year, day: i16) -> Result<Date, Error> {
-    type DayOfYear = ri16<1, 366>;
-
-    let day = DayOfYear::try_new("day-of-year", day)?;
+    let day = t::DayOfYear::try_new("day-of-year", day)?;
     let span = Span::new().days_ranged(day - C(1));
     let start = Date::new_ranged(year, C(1), C(1))?;
     let end = start.checked_add(span)?;