Inconsistent wording and broken links regarding assertions

Assertions have been renamed to "rules" in ADL2. However, all around the text there are still multiple references to assertions (I believe that even in the grammar). In fact, and probably due to changing the anchors targets, links like "[Assertions]" in rules section seem to be broken (see http://www.openehr.org/releases/AM/latest/docs/ADL2/ADL2.html#_rules_section)