Support Java snippet for main function

Should output: `public static void main(String[] args)`. More of these Java
snippets to come.

configs/shared/emacs/.emacs.d/snippets/java-mode/public-static-void-main

@@ -0,0 +1,7 @@
+# -*- mode: snippet -*-
+# name: public static void main
+# key: psvm
+# --
+public static void main(String[] args) {
+    $1
+}