PATCH: Clarify warning message documentation that e.g. \q is reservedfor future use.

Perhaps these messages should be reclassified as deprecated?

I'm not entirely happy with my wording; so maybe this will spur someone 
else to improve it.

• PATCH: Clarify warning message documentation that e.g. \q is reservedfor future use. by karl williamson
• Revised PATCH: Clarify warning message documentation that e.g. \qis reserved for future use. by karl williamson
• Re: Revised PATCH: Clarify warning message documentation that e.g. \q is reserved for future use. by Rafael Garcia-Suarez