home_and_end_beginning_end_of_doc=false doesn't affect shift+home and shift+end

The `preferences.txt` setting `home_and_end_beginning_end_of_doc=false` doesn't affect shift+home and shift+end.

`end` will go to the end of the current line, like expected. However also pressing the shift modifier doesn't select everything from the current cursor to the end of the line, but to the end of the document. Idem for `home`.

This affect only OSX.

Start with the home_and_end_beginning_end_of_doc setting in preferences.txt and trace the macOS handling of Home, End, Shift+Home, and Shift+End. Reproduce the behavior on OSX and verify that the setting makes Shift+Home and Shift+End select only to the current line boundary rather than the document boundary.

Written by the indexing model from the issue text.