fix: improve description and correct plot for ‘auto’ correlation (#1119)

* fix: correct plot and formatting for ‘auto’ correlation

* fix: create example ‘auto’ correlation notebook

* fix: add example for 'auto' correlation in python script

examples/features/correlation_auto_example.py

@@ -0,0 +1,36 @@
+from pathlib import Path
+import pandas as pd
+
+from pandas_profiling import ProfileReport
+from pandas_profiling.utils.cache import cache_zipped_file
+
+"""
+The "Auto" correlation is an interpretable pairwise column metric of the following mapping:
+
+- Variable_type-Variable_type : Method, **Range** 
+- Categorical-Categorical     : Cramer's V, **[0,1]**
+- Numerical-Categorical       : Cramer's V, **[0,1]** (using a discretized numerical column)
+- Numerical-Numerical         : Spearman's Rho, **[-1,1]**
+
+"""
+
+# Download the UCI Bank Marketing Dataset- as seen in examples/bank_marketing_data/banking_data.py
+file_name = cache_zipped_file(
+    "bank-full.csv",
+    "https://archive.ics.uci.edu/ml/machine-learning-databases/00222/bank.zip",
+)
+
+df = pd.read_csv(file_name, sep=";")
+
+profile = ProfileReport(
+    df, title="Profile Report of the UCI Bank Marketing Dataset", explorative=True
+)
+
+
+# The simplest way to change the number of bins is either through your script or notebook.
+# This changes the granularity of the association measure for Numerical-Categorical column pairs.
+profile.config.correlations["auto"].n_bins = 8
+
+
+# The 'auto' correlation matrix is displayed with the other correlation matrices in the report.
+profile.to_file(Path("uci_bank_marketing_report.html"))