[discovery-api] Editorial comments

A few editorial comments:

In the algorithm for getNetworkServices()
Step 16: s/the number of items currently found in the list of available
service records whose type property matches any of the tokens requested in
requested control types/the number of items in services found.

In Section 7 Service Discovery, in the introductory text,
- [[At any point during the running of either of the two service discovery
mechanisms then existing entries within this table can be updated]] s/either
of the two/any of the three/

In Section 7.3 Discovery and Launch Protocol, in the rule for obtaining a DIAL
Device Description File,
- the dial search target is not passed in as an argument but is used in the 
algorithm.
- inconsistent use of the terms "device descriptor file" and "descriptor 
file".

Finally, there needs to be a normative reference to the DIAL protocol.

- Cathy.