Misc fixes on bitshares-ags page.

- Absorbed sentence fragment into introductory sentence.
- Fixed run-on sentence.
- Made link to blockchain.info page more resilient to sitemap reorgs*

\* Indicates "meta" fix that does not affect how the content is displayed.

PTS addy PZ32Dv8NA1CBNtYyu5Z14qWNL6VWDSP4HC