Update type annotation of Linspace and Points

[NoureldinYosri]

Description of the issue
Linspace and Points have type annotations that use only floats ... however there is nothing in their operations that doesn't allow using other datatypes that as long as they support arithmetic operations. for example the following example is valid and works

In [1]: import cirq

In [2]: import tunits

In [3]: for t in cirq.Linspace('t', tunits.ns, 3*tunits.ns, 10):
   ...:     print(t)
   ...: 
cirq.ParamResolver({'t': Time(1.0, 'ns')})
cirq.ParamResolver({'t': Time(1.222222222222222, 'ns')})
cirq.ParamResolver({'t': Time(1.4444444444444444, 'ns')})
cirq.ParamResolver({'t': Time(1.6666666666666667, 'ns')})
cirq.ParamResolver({'t': Time(1.8888888888888888, 'ns')})
cirq.ParamResolver({'t': Time(2.111111111111111, 'ns')})
cirq.ParamResolver({'t': Time(2.3333333333333335, 'ns')})
cirq.ParamResolver({'t': Time(2.555555555555556, 'ns')})
cirq.ParamResolver({'t': Time(2.7777777777777777, 'ns')})
cirq.ParamResolver({'t': Time(3.0, 'ns')})

functionally the sweeps work but the type annotations need to be updated to reflect that

related to #6829

[dstrain115]

@NoureldinYosri I think this would break a bunch of other things if we change this, since these should resolve to TParamVal which is a float and used everywhere.

I don't think this is something easily changed. If you agree, let's close the issue.