Update src/tests/adding.md

Co-authored-by: Yuki Okushi <[email protected]>

Author: 2 people

src/tests/adding.md

@@ -196,7 +196,7 @@ emit. They are "attached" to the line in source where the error is
 located. Error annotations are considered during tidy lints of line
 length and should be formatted according to tidy requirements. You may
 use an error message prefix sub-string if necessary to meet line length 
-requirements.  Make sure that the text is long enough for the error 
+requirements. Make sure that the text is long enough for the error 
 message to be self-documenting.
 
 The error annotation definition and source line definition association