Plot the final datapoint correctly based on the waveform, instead of copying the previous one

Explanation of changes

In all plots the final datapoint is now (duration, waveform(duration) instead of (duration, waveform(duration - 1/samplingrate).

This fixes for example the ramp being flat during the last sample. Now it looks like a proper triangle reaching amp.

That does mean the implementations of waveform(t: np.ndarray) should not depend on the length of t or specific (other) values in t. ramp staircase and chirp have been adjusted accordingly. ramp(np.array([10, 2, 4, 1, 7]), ...) will work just fine now for example.

drag should probably also be adjusted (only the mu = t[0] - duration/2 part should just be mu = duration/2, as all t[0] has to be 0 anyway in the current/old implementations). ramp(np.array([10, 2, 4, 1, 7]), ...) will not work fine and never has.
I didn't adjust that as drag is probably the most used waveform, afraid touching it would break things.

Motivation of changes

The final datapoint is actually duration - epsilon, as the pulse is surrounded by 0s. We could change that final 0 to be plotted at duration + epsilon instead of duration. Does not matter too much

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• Merge request has been reviewed (in-depth by a knowledgeable contributor), and is approved by a project maintainer.
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