Deprecate matedialog (linux).

README.md

@@ -36,5 +36,5 @@ Why reinvent this particular wheel?
   * only dependency is `osascript` (with [JXA](https://developer.apple.com/library/archive/releasenotes/InterapplicationCommunication/RN-JavaScriptForAutomation/Articles/Introduction.html))
     * JavaScript is easier to template with `html/template`
 * on other UNIXes:
-  * wraps either one of `matedialog`, `qarma`, `zenity`
-    * in that order of preference, most to least specific
+  * wraps either one of `qarma`, `zenity`, `matedialog`
+    * in that order of preference

internal/zen/zen_unix.go

@@ -13,7 +13,7 @@ import (
 var tool, path string
 
 func init() {
-	for _, tool = range [3]string{"matedialog", "qarma", "zenity"} {
+	for _, tool = range [3]string{"qarma", "zenity", "matedialog"} {
 		path, _ = exec.LookPath(tool)
 		if path != "" {
 			return