Usability: Improve text for blog.module

Self-explanatory. The sole change (with this patch) is in the help file:

- $output = '

' . t('The blog module allows registered users to maintain an online journal, or blog. Blogs are made up of individual blog entries, and the blog entries are most often displayed in descending order by creation time.') . '

';
+ $output = '

' . t('The blog module allows registered users to maintain an online journal, or blog. Blogs are made up of individual blog entries which are usually displayed in reverse chronological order.') . '

';

Feel free to poke through blog.module in general and find fixes..... this was the one I could find, but improvements are welcome (obviously).