Improve the path select GUI (#5852)

- Allow lua to chose whatever directories or files can be selected
- Fix selecting directories
- Rename dialog to `guiPathSelectMenu` from `guiFileSelectMenu`
- Rename lua function for opening the menu from `show_file_open_dialog` to `show_path_select_dialog`
- Remove duplicate code and fix code style.

Related changes
- fix `clang-format` whitelist.
- Regenerate minetest.conf.example

builtin/mainmenu/dlg_settings_advanced.lua

@@ -196,7 +196,7 @@ local function parse_setting_line(settings, line, read_all, base_level, allow_se
 		return
 	end
 
-	if setting_type == "path" then
+	if setting_type == "path" or setting_type == "filepath" then
 		local default = remaining_line:match("^(.*)$")
 
 		if not default then
@@ -206,7 +206,7 @@ local function parse_setting_line(settings, line, read_all, base_level, allow_se
 		table.insert(settings, {
 			name = name,
 			readable_name = readable_name,
-			type = "path",
+			type = setting_type,
 			default = default,
 			comment = current_comment,
 		})
@@ -504,14 +504,14 @@ local function create_change_setting_formspec(dialogdata)
 		end
 		formspec = formspec .. ";" .. selected_index .. "]"
 
-	elseif setting.type == "path" then
+	elseif setting.type == "path" or setting.type == "filepath" then
 		local current_value = dialogdata.selected_path
 		if not current_value then
 			current_value = get_current_value(setting)
 		end
 		formspec = formspec .. "field[0.5,4;7.5,1;te_setting_value;;"
 				.. core.formspec_escape(current_value) .. "]"
-				.. "button[8,3.75;2,1;btn_browser_path;" .. fgettext("Browse") .. "]"
+				.. "button[8,3.75;2,1;btn_browser_" .. setting.type .. ";" .. fgettext("Browse") .. "]"
 
 	else
 		-- TODO: fancy input for float, int, flags, noise_params, v3f
@@ -606,7 +606,13 @@ local function handle_change_setting_buttons(this, fields)
 	end
 
 	if fields["btn_browser_path"] then
-		core.show_file_open_dialog("dlg_browse_path", fgettext_ne("Select path"))
+		core.show_path_select_dialog("dlg_browse_path",
+			fgettext_ne("Select directory"), false)
+	end
+
+	if fields["btn_browser_filepath"] then
+		core.show_path_select_dialog("dlg_browse_path",
+			fgettext_ne("Select file"), true)
 	end
 
 	if fields["dlg_browse_path_accepted"] then

builtin/settingtypes.txt

@@ -12,6 +12,7 @@
 #    - float
 #    - enum
 #    - path
+#    - filepath
 #    - key (will be ignored in GUI, since a special key change dialog exists)
 #    - flags
 #    - noise_params
@@ -31,6 +32,8 @@
 #            - default value1,value2,...
 #   * path:
 #            - default (if default is not specified then "" is set)
+#   * filepath:
+#            - default (if default is not specified then "" is set)
 #   * key:
 #            - default
 #   * flags:
@@ -642,7 +645,7 @@ tooltip_show_delay (Tooltip delay) int 400
 freetype (Freetype fonts) bool true
 
 #    Path to TrueTypeFont or bitmap.
-font_path (Font path) path fonts/liberationsans.ttf
+font_path (Font path) filepath fonts/liberationsans.ttf
 
 font_size (Font size) int 16
 
@@ -652,12 +655,12 @@ font_shadow (Font shadow) int 1
 #    Font shadow alpha (opaqueness, between 0 and 255).
 font_shadow_alpha (Font shadow alpha) int 127 0 255
 
-mono_font_path (Monospace font path) path fonts/liberationmono.ttf
+mono_font_path (Monospace font path) filepath fonts/liberationmono.ttf
 
 mono_font_size (Monospace font size) int 15
 
 #    This font will be used for certain languages.
-fallback_font_path (Fallback font) path fonts/DroidSansFallbackFull.ttf
+fallback_font_path (Fallback font) filepath fonts/DroidSansFallbackFull.ttf
 fallback_font_size (Fallback font size) int 15
 fallback_font_shadow (Fallback font shadow) int 1
 fallback_font_shadow_alpha (Fallback font shadow alpha) int 128 0 255