fix regexes in #quote-paragraph rule, and downstream

[andrewcarver]

trafficstars

Addresses a problem in the grammar: As it stands, the regex in rule #quote-paragraph will not match any block-attribute-list that contains, itself, an inline macro -- such as a URL macro or a bibliographic-citation macro. Downstream from that rule, there are weaknesses also in the #block-attribute-inner rule. The fixes I've applied here are based on earlier discussion of this whole matter in atom-language-asciidoc PR 197 -- where there are screen-shots and syntax-examples.

Resolves #767.