Fix: update naming

[Tuditi]

Description of change

The naming of prepareVotingPower() isn't consistent with prepareDecreaseVotingPower() & the method called through the bindings . I deprecated the previous function and added prepareIncreaseVotingPower()

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• Bug fix (a non-breaking change which fixes an issue)

How the change has been tested

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Change checklist

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• I have followed the contribution guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have checked that new and existing unit tests pass locally with my changes