Fix typos in the help message

1. Several small typos are fixed.
2. The adjective "same" is always preceded by the article "the".
3. The word "etc." is always preceded by a comma.
4. The past participle of the verb "run" is "run" instead of "ran".
5. Add comma after an if clause.
6. Add space after a period and before another sentence.
7. Add space after a comma and before another word.