Update MTM documentation to show defaults value

[khider]

Update the MTM documentation to reflect the default values for NW and appropriate choices.

[CommonClimate]

I added this to the documentation of Series.spectral() but we now have a new problem: all other methods have adjustable parameters, which we also need to explain and demonstrate how they can be changed. How should we do so?

[khider]

I think we should not have this in the doc, but rather point to the tutorial. Or have it under each functions rather than Series.Spectral

[CommonClimate]

"I think we should not have this in the doc, but rather point to the tutorial." Then why call the issue "Update MTM documentation..."? ;-)

I did consider updating the mtm function docstrings, but I think the spectral() docstring should show how to customize the calls via settings, as this is something I still have a hard time with as a developer, so I can't imagine users will have an easy time of it. That is, having to look up the notation of a parameter in the underlying function and trying it out in dictionary form can be tedious. I think users will be grateful for (terse) pointers to customizations.

[khider]

Because the doctoring didn't even mention which values of NW would be appropriate nor what the parameters would do (as in, this is the parameter close to Matlab). At least we should align to the native doc, which is where I found my answer.

So I would have 1 example in series.spectral on how to use settings for one of the functions. And if you want to put examples of the effect then put it with the underlying functions. but again, this is more a tutorial than pure doc.

[CommonClimate]

Even if we don't generate a new figure for each customization, there would no harm in saying: "This method is controlled by the parameter P, which means ____ . To change it, pass settings = {'P": value} to spectral() "

[CommonClimate]

I just don't see the point of a documentation that only shows defaults

[CommonClimate]

Case in point: the Series.wavelet() documentation shows how change the mother wavelet, for instance.

[khider]

Added good choice values for NW in 0d59b5

[khider]

Done in d61524