Update doc/python/hover-text-and-formatting.md

Author: LiamConnors

doc/python/hover-text-and-formatting.md

@@ -372,7 +372,8 @@ fig.show()
 ### Advanced Hover Template
 
 This produces the same graphic as in "Specifying the formatting and labeling of custom fields in a Plotly Express figure using a hovertemplate" above, but does so with the `customdata` and `text` parameters of `graph_objects`.  It shows how to specify columns from a dataframe to include in the customdata array using the df[["col_i", "col_j"]] subsetting notation.  It then references those variables using e.g. %{customdata[0]} in the hovertemplate.  It includes comments about major differences between the parameters used by `graph_objects` and `plotly.express`.  
-```
+
+```python
 import plotly.graph_objects as go
 import plotly.express as px
 import pandas as pd