Add the uDisplay trait for String incl test.

Did not add `uDisplay` for `Vec` because there is no trivial implementation.

# Conflicts:
#	Cargo.toml
#	src/ufmt.rs

Author: lmbollen

CHANGELOG.md

@@ -43,6 +43,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Implemented `PartialEq` and `Eq` for `Deque`.
 - Added `truncate` to `IndexMap`.
 - Added `get_index` and `get_index_mut` to `IndexMap`.
+- Added `String::uDisplay`.
 
 ### Changed
 

Cargo.toml

@@ -47,13 +47,13 @@ hash32 = "0.3.0"
 serde = { version = "1", optional = true, default-features = false }
 ufmt-write = { version = "0.1", optional = true }
 defmt = { version = "1.0.1", optional = true }
+ufmt = "0.2"
 
 # for the pool module
 [target.'cfg(any(target_arch = "arm", target_pointer_width = "32", target_pointer_width = "64"))'.dependencies]
 stable_deref_trait = { version = "1", default-features = false }
 
 [dev-dependencies]
-ufmt = "0.2"
 static_assertions = "1.1.0"
 
 [package.metadata.docs.rs]

src/ufmt.rs

@@ -3,8 +3,18 @@ use crate::{
     vec::{VecInner, VecStorage},
     CapacityError,
 };
+use ufmt::uDisplay;
 use ufmt_write::uWrite;
 
+impl<S: StringStorage + ?Sized> uDisplay for StringInner<S> {
+    fn fmt<W>(&self, f: &mut ufmt::Formatter<'_, W>) -> Result<(), W::Error>
+    where
+        W: uWrite + ?Sized,
+    {
+        f.write_str(&self.as_str())
+    }
+}
+
 impl<S: StringStorage + ?Sized> uWrite for StringInner<S> {
     type Error = CapacityError;
     fn write_str(&mut self, s: &str) -> Result<(), Self::Error> {
@@ -32,7 +42,16 @@ mod tests {
     }
 
     #[test]
-    fn test_string() {
+    fn test_udisplay_string() {
+        let str_a = String::<32>::try_from("world").unwrap();
+        let mut str_b = String::<32>::new();
+        uwrite!(str_b, "Hello {}!", str_a).unwrap();
+
+        assert_eq!(str_b, "Hello world!");
+    }
+
+    #[test]
+    fn test_uwrite_string() {
         let a = 123;
         let b = Pair { x: 0, y: 1234 };
 
@@ -43,14 +62,14 @@ mod tests {
     }
 
     #[test]
-    fn test_string_err() {
+    fn test_uwrite_string_err() {
         let p = Pair { x: 0, y: 1234 };
         let mut s = String::<4>::new();
         assert!(uwrite!(s, "{:?}", p).is_err());
     }
 
     #[test]
-    fn test_vec() {
+    fn test_uwrite_vec() {
         let a = 123;
         let b = Pair { x: 0, y: 1234 };