Rename values for method kwarg in TrotterProduct class

[Jaybsoni]

Context:
Rename the accepted values for the method keyword argument in the TrotterProduct class to be more verbose.

Description of the Change:
Change:

• method="one-norm" --> method="one-norm-bound"
• method="commutator" --> method="commutator-bound"

[github-actions]

Hello. You may have forgotten to update the changelog!
Please edit doc/releases/changelog-dev.md with:

• A one-to-two sentence description of the change. You may include a small working example for new features.
• A link back to this PR.
• Your name (or GitHub username) in the contributors section.

[soranjh]

Looks good.

[DSGuala]

Nice! Thanks for getting this in so fast.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (v0.36.0-rc0@be9f86a). Click here to learn what that means.

Additional details and impacted files

@@              Coverage Diff               @@
##             v0.36.0-rc0    #5637   +/-   ##
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  Coverage               ?   99.69%           
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  Files                  ?      412           
  Lines                  ?    38336           
  Branches               ?        0           
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  Hits                   ?    38218           
  Misses                 ?      118           
  Partials               ?        0           

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