minor corrections to devref rpc page

Correct wording to proper English and remove extra space between words while
in there.

DocImpact

Change-Id: If4b3d9d81d7193107e84867e4ab713c413a4976d
Remove XML namespace from some v3 extensions

The XML support was removed from the V3 API plugins,
this XML namespace was not used again.

Change-Id: I427597dd3f6d454037a791f911756a97f343966d
Merge "Remove XML namespace from some v3 extensions"
Merge "minor corrections to devref rpc page"