Remove Copy bound

We don't use it ourselves, so lets be permissive.

Author: matklad

src/traits.rs

@@ -4,7 +4,7 @@ use {
 };
 
 /// Text-like structures that have a text size.
-pub trait TextSized: Copy {
+pub trait TextSized {
     /// The size of this text-alike.
     fn text_size(self) -> TextSize;
 }