Minor FS documentation change from #2904 (#6563)
Minor FS documentation change from #2904 (#6563)

* Minor FS documentation change from #2904

Trivial addition to filesystem upload documentation.

Supercedes #2904 which cannot merge due to file renames and massive
changes to the filesystem.rst file since it was pushed.

* Fix periods on the steps, they are complete sentences

esp8266/Arduino,sticilface/Arduino,esp8266/Arduino,esp8266/Arduino,sticilface/Arduino,sticilface/Arduino,sticilface/Arduino,esp8266/Arduino,esp8266/Arduino,sticilface/Arduino