termux-tools: improve default motd

packages/termux-tools/motd

@@ -1,3 +1,4 @@
+
 Welcome to Termux!
 
 Wiki:            https://wiki.termux.com
@@ -6,7 +7,19 @@ IRC channel:     #termux on freenode
 Gitter chat:     https://gitter.im/termux/termux
 Mailing list:    termux+subscribe@groups.io
 
-Search packages:   pkg search <query>
+Working with packages:
-Install a package: pkg install <package>
+
-Upgrade packages:  pkg upgrade
+ * Search packages:   pkg search <query>
-Learn more:        pkg help
+ * Install a package: pkg install <package>
+ * Upgrade packages:  pkg upgrade
+ * Learn more:        pkg help
+
+Subscribing to additional repositories:
+
+ * Root:     pkg install root-repo
+ * Unstable: pkg install unstable-repo
+ * X11:      pkg install x11-repo
+
+App issues: https://github.com/termux/termux-app/issues
+Package issues: https://github.com/termux/termux-packages/issues
+