Unifying DataLocale construction (#4912)

In preparation for #3632 

There are two cases:
* `DataLocales` that are passed into ICU4X constructors:
* These are constructed with `locale!("foo").into()`, or `"foo".parse()`
* When changing a constructor to preferences, the code doesn't need to
be changed if we add a `From<Locale>` impl for the preferences
* `DataLocales` that are put into the `DataRequest::locale` field.
* These are constructed with `langid!("foo").into()`, or `"foo".parse()`
* When changing the field to `&LanguageIdentifier`, these can be
clippy-cleaned-up, as the `.into()` will become redundant.

I've taken care to avoid having intermediate `Locale` or
`LanguageIdentifier` variables, everything that is macro-constructed is
immediately `into()`ed. This will simplify find-and-replace later.

components/calendar/src/week_of.rs

@@ -711,34 +711,34 @@ fn test_simple_week_of() {
 
 #[test]
 fn test_weekend() {
-    use icu_locid::langid;
+    use icu_locid::locale;
 
     assert_eq!(
-        WeekCalculator::try_new(&langid!("und").into())
+        WeekCalculator::try_new(&locale!("und").into())
             .unwrap()
             .weekend()
             .collect::<Vec<_>>(),
         vec![IsoWeekday::Saturday, IsoWeekday::Sunday],
     );
 
     assert_eq!(
-        WeekCalculator::try_new(&langid!("und-FR").into())
+        WeekCalculator::try_new(&locale!("und-FR").into())
             .unwrap()
             .weekend()
             .collect::<Vec<_>>(),
         vec![IsoWeekday::Saturday, IsoWeekday::Sunday],
     );
 
     assert_eq!(
-        WeekCalculator::try_new(&langid!("und-IQ").into())
+        WeekCalculator::try_new(&locale!("und-IQ").into())
             .unwrap()
             .weekend()
             .collect::<Vec<_>>(),
         vec![IsoWeekday::Saturday, IsoWeekday::Friday],
     );
 
     assert_eq!(
-        WeekCalculator::try_new(&langid!("und-IR").into())
+        WeekCalculator::try_new(&locale!("und-IR").into())
             .unwrap()
             .weekend()
             .collect::<Vec<_>>(),

components/collator/src/lib.rs

@@ -41,22 +41,22 @@
 //! ```
 //! use core::cmp::Ordering;
 //! use icu::collator::*;
-//! use icu::locid::{locale, Locale};
+//! use icu::locid::locale;
 //!
-//! let locale_es: Locale = locale!("es-u-co-trad");
+//! let locale_es = locale!("es-u-co-trad").into();
 //! let mut options = CollatorOptions::new();
 //! options.strength = Some(Strength::Primary);
 //! let collator_es: Collator =
-//!     Collator::try_new(&locale_es.into(), options).unwrap();
+//!     Collator::try_new(&locale_es, options).unwrap();
 //!
 //! // "pollo" > "polvo" in traditional Spanish
 //! assert_eq!(collator_es.compare("pollo", "polvo"), Ordering::Greater);
 //!
-//! let locale_en: Locale = locale!("en");
+//! let locale_en = locale!("en").into();
 //! let mut options = CollatorOptions::new();
 //! options.strength = Some(Strength::Primary);
 //! let collator_en: Collator =
-//!     Collator::try_new(&locale_en.into(), options).unwrap();
+//!     Collator::try_new(&locale_en, options).unwrap();
 //!
 //! // "pollo" < "polvo" according to English rules
 //! assert_eq!(collator_en.compare("pollo", "polvo"), Ordering::Less);

components/collator/src/options.rs

@@ -85,10 +85,9 @@ pub enum Strength {
     /// assert_eq!(collator.compare("e", "ｅ"), // Full-width e
     ///            core::cmp::Ordering::Less);
     ///
-    /// let locale = icu::locid::locale!("ja");
+    /// let locale = icu::locid::locale!("ja").into();
     /// let ja_collator =
-    ///   Collator::try_new(&locale.into(),
-    ///                     options).unwrap();
+    ///   Collator::try_new(&locale, options).unwrap();
     /// assert_eq!(ja_collator.compare("E", "e"),
     ///            core::cmp::Ordering::Greater);
     /// assert_eq!(ja_collator.compare("e", "é"),
@@ -116,10 +115,9 @@ pub enum Strength {
     /// let mut options = CollatorOptions::new();
     /// options.strength = Some(Strength::Quaternary);
     ///
-    /// let ja_locale = icu::locid::locale!("ja");
+    /// let ja_locale = icu::locid::locale!("ja").into();
     /// let ja_collator =
-    ///   Collator::try_new(&ja_locale.into(),
-    ///                     options).unwrap();
+    ///   Collator::try_new(&ja_locale, options).unwrap();
     /// assert_eq!(ja_collator.compare("あ", "ア"),
     ///            core::cmp::Ordering::Less);
     /// assert_eq!(ja_collator.compare("ア", "ｱ"),
@@ -153,10 +151,9 @@ pub enum Strength {
     /// let mut options = CollatorOptions::new();
     /// options.strength = Some(Strength::Identical);
     ///
-    /// let ja_locale = icu::locid::locale!("ja");
+    /// let ja_locale = icu::locid::locale!("ja").into();
     /// let ja_collator =
-    ///   Collator::try_new(&ja_locale.into(),
-    ///                     options).unwrap();
+    ///   Collator::try_new(&ja_locale, options).unwrap();
     /// assert_eq!(ja_collator.compare("ア", "ｱ"),
     ///            core::cmp::Ordering::Less);
     /// assert_eq!(ja_collator.compare("e", "ｅ"), // Full-width e