Clean up E0025, E0034, E0044, E0046 and E0053

Author: GuillaumeGomez

src/librustc_error_codes/error_codes/E0025.md

@@ -1,5 +1,6 @@
-Each field of a struct can only be bound once in a pattern. Erroneous code
-example:
+Each field of a struct can only be bound once in a pattern.
+
+Erroneous code example:
 
 ```compile_fail,E0025
 struct Foo {

src/librustc_error_codes/error_codes/E0034.md

@@ -1,5 +1,7 @@
 The compiler doesn't know what method to call because more than one method
-has the same prototype. Erroneous code example:
+has the same prototype.
+
+Erroneous code example:
 
 ```compile_fail,E0034
 struct Test;

src/librustc_error_codes/error_codes/E0044.md

@@ -1,4 +1,5 @@
 You cannot use type or const parameters on foreign items.
+
 Example of erroneous code:
 
 ```compile_fail,E0044

src/librustc_error_codes/error_codes/E0046.md

@@ -1,4 +1,6 @@
-Items are missing in a trait implementation. Erroneous code example:
+Items are missing in a trait implementation.
+
+Erroneous code example:
 
 ```compile_fail,E0046
 trait Foo {

src/librustc_error_codes/error_codes/E0053.md

@@ -1,7 +1,7 @@
 The parameters of any trait method must match between a trait implementation
 and the trait definition.
 
-Here are a couple examples of this error:
+Erroneous code example:
 
 ```compile_fail,E0053
 trait Foo {