Update __HOTDIR__.md (#70)

fixed typo for text.

collector/hotdir/__HOTDIR__.md

@@ -8,10 +8,10 @@ Once converted the original file will be moved to the `hotdir/processed` folder
 
 **Supported File types**
 - `.md`
-- `.text`
+- `.txt`
 - `.pdf`
 
 __requires more development__
 - `.png .jpg etc`
 - `.mp3`
-- `.mp4`
\ No newline at end of file
+- `.mp4`