fix: remove unnecessary Sized boundaries (prometheus#274)

Signed-off-by: slonkazoid <slonkazoid@slonk.ing>

Author: slonkazoid

src/encoding.rs

@@ -416,6 +416,7 @@ impl EncodeLabelKey for Cow<'_, str> {
 
 impl<T> EncodeLabelKey for Box<T>
 where
+    T: ?Sized,
     for<'a> &'a T: EncodeLabelKey,
 {
     fn encode(&self, encoder: &mut LabelKeyEncoder) -> Result<(), std::fmt::Error> {
@@ -425,6 +426,7 @@ where
 
 impl<T> EncodeLabelKey for Arc<T>
 where
+    T: ?Sized,
     for<'a> &'a T: EncodeLabelKey,
 {
     fn encode(&self, encoder: &mut LabelKeyEncoder) -> Result<(), std::fmt::Error> {
@@ -434,6 +436,7 @@ where
 
 impl<T> EncodeLabelKey for Rc<T>
 where
+    T: ?Sized,
     for<'a> &'a T: EncodeLabelKey,
 {
     fn encode(&self, encoder: &mut LabelKeyEncoder) -> Result<(), std::fmt::Error> {
@@ -511,6 +514,7 @@ impl EncodeLabelValue for Cow<'_, str> {
 
 impl<T> EncodeLabelValue for Box<T>
 where
+    T: ?Sized,
     for<'a> &'a T: EncodeLabelValue,
 {
     fn encode(&self, encoder: &mut LabelValueEncoder) -> Result<(), std::fmt::Error> {
@@ -520,6 +524,7 @@ where
 
 impl<T> EncodeLabelValue for Arc<T>
 where
+    T: ?Sized,
     for<'a> &'a T: EncodeLabelValue,
 {
     fn encode(&self, encoder: &mut LabelValueEncoder) -> Result<(), std::fmt::Error> {
@@ -529,6 +534,7 @@ where
 
 impl<T> EncodeLabelValue for Rc<T>
 where
+    T: ?Sized,
     for<'a> &'a T: EncodeLabelValue,
 {
     fn encode(&self, encoder: &mut LabelValueEncoder) -> Result<(), std::fmt::Error> {