docs: fix hasMany diagram L&F

[dhmlau]

Change the L&F of the hasMany diagram to something similar to the todo overview digram.

Fixes #1532

[marioestradarosa]

How about this one? . I think the customerId on Order table should be number.

[dhmlau]

@marioestradarosa , thanks for catching the error. I like your diagram!
May I know what software do you use to create the diagram? Cannot find the arrow style in PowerPoint.

We're trying to use these color palettes for the LB4 documentation diagrams. If you could modify your diagram using those colors (I think only the green is off?), please feel free to submit another PR, I'm happy to abandon this one.

[marioestradarosa]

@dhmlau I used Keynote and the many arrow is coming from one of the connectors (actually you have to mold it a little bit). I am color blind, so I think I never saw the green line :-) . don't worry about the PR you can use the diagram on this PR. If you want me to send you the KeyNote file, I will send it to you.

[b-admike]

Thank you for fixing this @dhmlau @marioestradarosa, the new one is looking great 👍

[dhmlau]

Thanks @marioestradarosa. I've updated with your diagram.

[dhmlau]

Thanks @marioestradarosa. The PR has merged. :)