Rollup merge of #72976 - GuillaumeGomez:cleanup-e0642, r=Dylan-DPC

Clean up E0642 explanation

r? @Dylan-DPC

src/librustc_error_codes/error_codes/E0642.md

 Trait methods currently cannot take patterns as arguments.
 
-Example of erroneous code:
+Erroneous code example:
 
 ```compile_fail,E0642
 trait Foo {