Polish Matplotlib content for consistency

.gitignore

@@ -139,3 +139,4 @@ content/notebooks_gallery/
 
 # Notebook outputs
 core/pandas/nino_analyzed_output.csv
+core/matplotlib/animate.gif

_toc.yml

@@ -42,9 +42,9 @@ parts:
           - file: core/numpy/numpy-broadcasting
       - file: core/matplotlib
         sections:
-          - file: core/matplotlib/matplotlib
-          - file: core/matplotlib/matplotlib-additional-topics-1
-          - file: core/matplotlib/additional-topics2
+          - file: core/matplotlib/matplotlib-basics
+          - file: core/matplotlib/histograms-piecharts-animation
+          - file: core/matplotlib/annotations-colorbars-layouts
       - file: core/cartopy
         sections:
           - file: core/cartopy/cartopy

core/matplotlib.md

@@ -18,8 +18,12 @@ This section contains tutorials on basic plotting with [Matplotlib](https://matp
 
 From the [Matplotlib documentation](https://matplotlib.org) "Matplotlib is a comprehensive library for creating static, animated, and interactive visualizations in Python."
 
-Currently, we provide a basic introduction to matplotlib, as well as:
-
-- Legend and annotation customization
+Currently, we provide a basic introduction to Matplotlib, as well as:
+
+- Histograms
+- Piecharts
+- Animations
+- Annotations
+- Colorbars
+- Contour plots
 - Customizing layouts
-- Interactive and 3D plotting