docs(ngMock): fixes in flush() documentation

The docs for the `flush()` method contained a few grammatical
errors and were awkwardly worded. Change the explanation of
the method to remove errors and read more naturally.

Closes #4886
docs(loader): change 'MyModule' -> 'myModule'

Closes #5393
docs(guide/injecting-services): fix list formatting in Related* sections

Closes #5447
docs(*): ensure jsdoc type expressions are valid
chore(package.json): update dgeni dependencies
docs(directives): ensure that the back-to-top directive resets location

Closes #6512
Closes #6499
docs(error/ng/btstrpd): note that loading angular.js twice can cause the error

Closes #6502
docs($interval): cancel() takes a promise not a number

Closes #6485
docs(ngView): rename controller suffix in ngView example

- According to
  https://github.com/angular/angular.js/blob/5bf81bc111a866ec65ef86c01336911e577df5df/docs/content/guide/controller.ngdoc#L166
  Ctrl should be the suffix for a controller

Closes #5817
docs(loader): remove duplicate "the"

Typo fixup

Closes #6521
docs(guide/expression): clarify
docs(guide/templates): clarity
docs(guide/services): rewrite services documentation
docs(guide/bootstrap): fix formatting
docs(guide/css-styling): rename and fix formatting
docs(guide/e2e-testing): rename and fix formatting
docs(guide/unit-testing): rename and fix formatting
docs(guide/introduction): reword for clarity
docs(guide/concepts): fix links
docs(guide/controller): reorganize, add Controller suffix, formatting