add an user preference for loading changed files without a prompt (bug #42678) * file-editor-tab.cc (file_has_changed): check user preference before prompting for reloading the file; (notice-settings): get flag for prompting before reloading file from settings; * file-editor-tab.h: new flag _always_reload_changed files * settings-dialog.ui: new check box for new preference * settings-dialog.cc (constructor): get state of new check box from settings; (write_changes_settings): write state of new check box into settings

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