Clustering example error fixed

[luisheb]

References to issues or other PRs

No issue was reported regarding the error in the clustering example.

Describe the proposed changes

In the clustering example, a couple of the explanations of the code did not match the code itself. For instance you could read:

To see the information in a graphic way, the method plot_clusters() can be used.

However, instead of using plot_clusters(), the following class was used:

ClusterPlot(kmeans, fd, cluster_colors=cluster_colors, cluster_labels=cluster_labels).plot()

Checklist before requesting a review

• [x] I have performed a self-review of my code
• [x] The code conforms to the style used in this package
• [x] The code is fully documented and typed (type-checked with Mypy)
• [x] I have added thorough tests for the new/changed functionality

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 86.83%. Comparing base (d0bc82f) to head (2f48baa). Report is 3 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #635 +/- ## ======================================== Coverage 86.83% 86.83% ======================================== Files 157 157 Lines 13522 13522 ======================================== Hits 11742 11742 Misses 1780 1780 ```

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[vnmabus]

@all-contributors Please add @luisheb for documentation.

[allcontributors[bot]]

@vnmabus

I've put up a pull request to add @luisheb! :tada: