Add ModuleNotFoundError explanation

docs/basics/common-errors.md

@@ -28,7 +28,8 @@ Errors that are relatively generic and can occur with any script or package.
 
 | Error                                                                                                                           | Meaning                                                                                                                                                                                                                         |
 | ------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| AttributeError: No attribute with the name '[plugin]' exists. Did you mistype a plugin namespace or forget to install a plugin? | The specified plugin doesn't exist. Check for typos and/or ensure the required plugin is installed.                                                                                                                             |
+| AttributeError: No attribute with the name '[plugin]' exists. Did you mistype a plugin namespace or forget to install a plugin? | The specified Vapoursynth plugin doesn't exist. Check for typos and/or ensure the required plugin is installed.                                                                                                                 |
+| ModuleNotFoundError: No module named '[package]'                                                                                | The specified Python package doesn't exist. Check for typos and/or ensure the required package is installed.                                                                                                                    |
 | ImportError: cannot import name '[name]' from '[package]'                                                                       | The specified functions, class, or variables cannot be imported from the given package. Check for typos and/or ensure the required packages is installed, or that the thing you're trying to import has been properly exported. |
 | ERROR: pip's dependency resolver does not currently take into account all the packages that are installed.                      | Warning that indicate pip might not be considering all installed packages when resolving dependencies. This is usually not a critical error, but is indicative of conflicts or inconsistencies in package versions.             |