Add explanatory text for error E0599

Add a text description of this error instead of just example error code

diff --git a/src/librustc_typeck/diagnostics.rs b/src/librustc_typeck/diagnostics.rs
index 8f91d07b53fb26fc39b5c5d69f86bfbbc55f929d..594cd0878cbfbc62144d3aabfed38bf24350174c 100644 (file)
--- a/src/librustc_typeck/diagnostics.rs
+++ b/src/librustc_typeck/diagnostics.rs
@@ -3986,6 +3986,10 @@ fn main() { }
 "##,
 
 E0599: r##"
+This error occurs when a method is used on a type which doesn't implement it:
+
+Erroneous code example:
+
 ```compile_fail,E0599
 struct Mouth;