Merge pull request #2883 from rust-lang/tshepang-patch-1

fix grammar

Author: tshepang

src/tests/ui.md

@@ -394,8 +394,8 @@ E.g. use `//@ dont-require-annotations: NOTE` to annotate notes selectively.
 Avoid using this directive for `ERROR`s and `WARN`ings, unless there's a serious reason, like
 target-dependent compiler output.
 
-Some diagnostics are never required to be line-annotated, regardless of their kind or directives,
-for example secondary lines of multiline diagnostics,
+Some diagnostics are never required to be line-annotated, regardless of their kind or directives.
+Examples are secondary lines of multiline diagnostics,
 or ubiquitous diagnostics like `aborting due to N previous errors`.
 
 UI tests use the `-A unused` flag by default to ignore all unused warnings, as