help: Modify world-remove.page

Remove <title> from the steps list
help: Modify index.page

Make Stopwatch the third section in the page, and Timer the fourth
section to reflect the order of the buttons in Clocks.
help: Modify world-add.page

Corrected language/grammar in the steps list.
help: Modify alarm-add.page

Add an introductory paragraph to alarm-add.page
help:Modify alarm-edit.page

Add introductory paragraph to alarm-edit.page
help: Modify alarm-remove.page

Change description and add a small introductory paragraph.
help: Modify stopwatch.page

Reword some steps. Title the steps list.
help: Modify timer.page

Remove the word "respectively".
Describe the notification given by the timer.
Add introductory <p> element.
help: Reflow some text in alarm-snooze-stop.page
help: Mark all pages for review.