Clean up E0516 explanation

GuillaumeGomez · GuillaumeGomez · commit d0b23d5b8338 · 2020-04-12T13:58:05.000+02:00
diff --git a/src/librustc_error_codes/error_codes/E0516.md b/src/librustc_error_codes/error_codes/E0516.md
@@ -1,4 +1,5 @@
 The `typeof` keyword is currently reserved but unimplemented.
+
 Erroneous code example:
 
 ```compile_fail,E0516

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	The `typeof` keyword is currently reserved but unimplemented.
	`2`	`+`
`2`	`3`	`Erroneous code example:`
`3`	`4`
`4`	`5`	```compile_fail,E0516