fix conflict between main and editor menus when using alt keys (bug #42659) * file-editor.cc (enable_menu_shortcuts): new function enabling/disabling the alt-key accelerators; (m_add_menu): new function adding a menu and storing menu title with and without the char & indicating the accelerator in a hash; (construct): use m_add_menu for adding a new menu to the menu bar * file-editor-interface.h: new virtual function enable_menu_shortcuts * file-editor.h: new functions enable_menu_shortcuts amd m_add_menu, new hash for storing the menu titles * main-window.cc (connect_visibility_changed): disable editors menu shortcuts; (enable_menu_shortcuts): new function enabling/disabling the alt-key accelerators; (m_add_menu): new function adding a menu and storing menu title with and without the char & indicating the accelerator in a hash; (construct_file_menu, construct_edit_menu, construct_debug_menu, construct_window_menu, construct_help_menu, construct_news_menu): use m_add_menu for adding a new menu to the menu bar; (set_global_edit_shortcuts): enable/disable the main and the editors menu shortcuts

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$
^doc/\w*/version\.texi$
^doc/interpreter/images\.mk$

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

^libinterp/dldfcn/module\.mk$