Add path to RenderDiagram for Ch2, Ex _01_reflected_inertia

[Jakeisthesnake]

[Note: I'm quite the beginner]

Got the following error when trying to visualize the block diagram: Execution error NameError: name 'RenderDiagram' is not defined

After adding path to utils, the error went away and the program displayed the proper diagram.

Aside: the follow edit looked cleaner and appeared to also solve the issue, but I wasn't sure if there was a reason for importing running_as_notebook from manipulation instead of from manipulation.utils modified line: from manipulation import running_as_notebook to: from manipulation.utils import running_as_notebook, RenderDiagram

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This change is