bindings: deprecate alt_/ctrl_/shift_ prefixes

doc/bindings

@@ -51,10 +51,10 @@
 ##      picked by ncmpcpp upon next call to readKey function.
 ##      Accepted values: mouse, up, down, page_up, page_down,
 ##      home, end, space, enter, insert, delete, left, right,
-##      tab, ctrl_a, ctrl_b, ..., ctrl_z, ctrl_[, ctrl_\\,
-##      ctrl_], ctrl_^, ctrl__, f1, f2, ..., f12, backspace.
+##      tab, ctrl-a, ctrl-b, ..., ctrl-z, ctrl-[, ctrl-\\,
+##      ctrl-], ctrl-^, ctrl-_, f1, f2, ..., f12, backspace.
 ##      In addition, most of these names can be prefixed with
-##      alt_/ctrl_/shift_ to be recognized with the appropriate
+##      alt-/ctrl-/shift- to be recognized with the appropriate
 ##      modifier key(s).
 ##
 ##    - push_characters "string" - pushes given string into
@@ -235,7 +235,7 @@
 #def_key "tab"
 #  next_screen
 #
-#def_key "shift_tab"
+#def_key "shift-tab"
 #  previous_screen
 #
 #def_key "f1"
@@ -292,10 +292,10 @@
 #def_key "<"
 #  previous
 #
-#def_key "ctrl_h"
+#def_key "ctrl-h"
 #  jump_to_parent_directory
 #
-#def_key "ctrl_h"
+#def_key "ctrl-h"
 #  replay_song
 #
 #def_key "backspace"
@@ -352,19 +352,19 @@
 #def_key "u"
 #  update_database
 #
-#def_key "ctrl_s"
+#def_key "ctrl-s"
 #  sort_playlist
 #
-#def_key "ctrl_s"
+#def_key "ctrl-s"
 #  toggle_browser_sort_mode
 #
-#def_key "ctrl_s"
+#def_key "ctrl-s"
 #  toggle_media_library_sort_mode
 #
-#def_key "ctrl_r"
+#def_key "ctrl-r"
 #  reverse_playlist
 #
-#def_key "ctrl__"
+#def_key "ctrl-_"
 #  select_found_items
 #
 #def_key "/"
@@ -418,7 +418,7 @@
 #def_key "l"
 #  show_lyrics
 #
-#def_key "ctrl_v"
+#def_key "ctrl-v"
 #  select_range
 #
 #def_key "v"
@@ -502,7 +502,7 @@
 #def_key "F"
 #  toggle_fetching_lyrics_in_background
 #
-#def_key "ctrl_l"
+#def_key "ctrl-l"
 #  toggle_screen_lock
 #
 #def_key "`"
@@ -514,7 +514,7 @@
 #def_key "`"
 #  add_random_items
 #
-#def_key "ctrl_p"
+#def_key "ctrl-p"
 #  set_selected_items_priority
 #
 #def_key "q"