Wrap reference asciidoc at 90 characters

Reformat the asciidoc source for the reference guide to wrap at about
90 characters.

Issue: SPR-11096
Replace asciidoc authors convention with attribute

Replace the second line of the asciidoc reference guide that, by
convention, specifies authors with an 'author' explicit attribute.

Issue: SPR-11096
Specify asciidoc type

Specify a specific asciidoc type of 'docbook' to prevent
'multiple titles at level 0' errors during generation.

Issue: SPR-11096
Remove superfluous space before 'http' in asciidoc

Remove the superfluous space that appears before each 'http' reference
in the asciidoc source. Presumably there due to some quirk of the
docbook conversion.

Issue: SPR-11096
Fix broken reference guide links

Remove or replace broken links from the reference documentation.

Issue: SPR-11096