doc: Minor updates for usage.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Minor updates.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Updated index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Updated index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Updated index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Updated for glossary usage. Index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Update for usage. Index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Update for usage and index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added introductory section. Updated usage. Index tags.

fixes: #3220

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Updated usage and index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Updated usage and index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added index tag.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added index tags.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>