Add missing quote in circuits.ipynb

[LaurentAjdnik]

Adds a missing quote in the Circuits notebook that causes incorrect display of the doc:

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[vtomole]

LGTM. Thanks!

[LaurentAjdnik]

@googlebot I signed it!

[vtomole]

Actually, one small thing: Could we change Operations to Operations because cirq.Operation exists, but not cirq.Operations.

[LaurentAjdnik]

Actually, one small thing: Could we change Operations to Operations because cirq.Operation exists, but not cirq.Operations.

I sure can. But Operations already appears as such eight times. Just like Moments is used twice instead of Moments.

Should I change them all? I agree this would be more logical.

[vtomole]

Oh i see. That's fine then. Let's leave it as-is because I bet the conventions that exist at the moment are not restricted to this file.