* docs(structural-directives): copyedits and some tweaks to code
- Fix variable name `li` --> `i`
- a --> an `UnlessDirective`
- Jade had both #ngswitch and #ngSwitch as link targets;
fixed to use same capitalization as template syntax page.
- Fixed broke fragment target (was missing #)
- Other copy edits and post-review comments from @wardbell
* de-sugar --> desugar
* fix h2 text capitalization
Move details of structural directives from template-syntax to structural-directives guide
Add <ng-container> to structural-directives
Fix samples in both guides
Touch up glossary
Better conformance to google doc guidelines: we->you
closes#2303, #2885
