QOL: Pre-fill Signal Right-Click menu with Script Methods

[Reelix]

Scenario: You have a Canvas button. The button has a script attached. You want the buttons pressed() event to call a pressed event in your script.

At the moment, you:

1. Click the button
2. Go to the Node tree
3. Double click the pressed() Signal (Or right-click -> connect)
4. Type the node name OR
5. Click "Pick"
6. Enable "Script Methods Only" or scroll down to your script method
7. Double-click the method name
8. Click connect

I propose that the Script Methods be added to the Right-Click menu of the Signal to auto-connect, so the process would be as follows:

1. Click the button
2. Go to the Node tree
3. Right-click the pressed() Signal
4. Choose the Method from the script in the context menu

This would remove multiple screens and options for a commonly used process.

Similar to #5193, but on the Node UI itself, and not on the inner Connect a Signal to a Method window.