docs/command-line-interface: Add "NOT RECOMMENDED" to RFC 2119 keywords

Catching up with erratum 499 [1].

[1]: https://www.rfc-editor.org/errata_search.php?rfc=2119&eid=499

Signed-off-by: W. Trevor King <[email protected]>

Author: wking

docs/command-line-interface.md

@@ -5,7 +5,7 @@ It is one of potentially several [runtime APIs supported by the runtime complian
 
 ## Notation
 
-The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC 2119][rfc2119].
+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 [RFC 2119][rfc2119].
 
 The key words "unspecified", "undefined", and "implementation-defined" are to be interpreted as described in the [rationale for the C99 standard][c99-unspecified].