Make the file browser open files more consistently (bug #45844) * files-dock-widget.cc (files_dock_widget::display_directory): open files in default app except for user defined extensions. Default: m,c,cc,cpp,h,txt * files-dock-widget.cc (files_dock_widget::contextmenu_requested): add action for opening files in the editor * files-dock-widget.cc (files_dock_widget::contextmenu_requested): remove "open in default app" menu and add "open in sytem file explorer" for dirs only. * files-dock-widget.cc (files_dock_widget::contextmenu_open): make use of display_directory for concistency * files-dock-widget.cc (files_dock_widget::contextmenu_open_in_editor): new slot to force opening a file in the editor * files-dock-widget.h: declare new slot "contextmenu_open_in_editor" * settings-dialog.ui: add new lineEdit and label for file extensions setting * settings-dialog.cc (settings_dialog::settings_dialog,::~settings_dialog): read/write new setting "filesdockwidget/txt_file_extensions". Default: m,c,cc,cpp,h,txt

syntax: regexp
# The recurrent (^|/) idiom in the regexps below should be understood
# to mean "at any directory" while the ^ idiom means "from the
# project's top-level directory".

# gnulib makes these silly backup files
.~$

# This directory gets created by gnulib during the build. 
# It contains no Octave files.
^libgnu/*

# This directory mostly contains cruft during build time, but it does
# contain some Octave code, so we gotta be a bit more careful about
# what we ignore here
^m4/(?!ax_).+\.m4$

# Emacs tools create these
(^|/)TAGS$
(^|/)semantic.cache$

(/|^)Makefile\.in$
^INSTALL$

^aclocal\.m4$
^build-.*($|/)
^configure$
^autom4te\.cache($|/)
^config\.in\.h$

# e.g. doc/faq/OctaveFAQ.info
#      doc/interpreter/octave.info-4
^doc/.*\.info(-\d)?$

^doc/\w*/stamp-(vti|\d+)$
^doc/\w*/version-\w+\.texi$
^doc/interpreter/images\.mk$

# e.g. liboctave/operators/smx-op-inc.mk
^liboctave/operators/\w+-op-\w+\.mk$

^libinterp/dldfcn/module\.mk$