Restructure icu_provider files (#2168)

Author: robertbastian

provider/core/README.md

@@ -87,8 +87,8 @@ data generation implementation.
 
 [`ICU4X`]: ../icu/index.html
 [`DataProvider`]: data_provider::DataProvider
-[`ResourceKey`]: resource::ResourceKey
-[`ResourceOptions`]: resource::ResourceOptions
+[`ResourceKey`]: key::ResourceKey
+[`ResourceOptions`]: request::ResourceOptions
 [`IterableDynProvider`]: datagen::IterableDynProvider
 [`IterableResourceProvider`]: datagen::IterableResourceProvider
 [`AnyPayloadProvider`]: ../icu_provider_adapters/any_payload/struct.AnyPayloadProvider.html

provider/core/src/any.rs

@@ -342,7 +342,6 @@ where
 mod test {
     use super::*;
     use crate::hello_world::*;
-    use crate::marker::CowStrMarker;
     use alloc::borrow::Cow;
 
     const CONST_DATA: HelloWorldV1<'static> = HelloWorldV1 {
@@ -361,9 +360,15 @@ mod test {
             format!("{:?}", any_payload)
         );
 
-        let err = any_payload.downcast::<CowStrMarker>().unwrap_err();
+        struct WrongMarker;
+
+        impl DataMarker for WrongMarker {
+            type Yokeable = u8;
+        }
+
+        let err = any_payload.downcast::<WrongMarker>().unwrap_err();
         assert_eq!(
-            "ICU4X data error: Mismatched types: tried to downcast with icu_provider::marker::impls::CowStrMarker, but actual type is different: icu_provider::hello_world::HelloWorldV1Marker",
+            "ICU4X data error: Mismatched types: tried to downcast with icu_provider::any::test::test_debug::WrongMarker, but actual type is different: icu_provider::hello_world::HelloWorldV1Marker",
             format!("{}", err)
         );
     }