Better and fixed shortcuts (mappings), including the new remapped key F8
that enables automatic language identification (on-the-fly language detection).

F5: Tries to automatically set buffer language based on the current line
F6: Tries to automatically set buffer language based on the current paragraph
F7: Tries to automatically set buffer language based on the whole buffer
F8: Enables automatic language identification, which is performed whenever
     the user change the buffer (remove the suffix 'Lazy' to call the
     language identification even if the user didn't change the buffer)
F9: Disables buffer spell checking, including auto language identification
     when it was enabled manually (via F8 shortcut)