Tweak punctuation

Signed-off-by: Flynn <[email protected]>

Author: kflynn

geps/gep-3949/index.md

@@ -11,8 +11,8 @@
 
 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
 "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this
-document are to be interpreted as described in BCP 14 [RFC8174] when, and only
-when, they appear in all capitals, as shown here.
+document are to be interpreted as described in BCP 14 ([RFC8174]) when, and
+only when, they appear in all capitals, as shown here.
 
 [RFC8174]: https://www.rfc-editor.org/rfc/rfc8174