Add inset_element to API reference

Author: has2k1

doc/_quartodoc.yml

@@ -548,6 +548,7 @@ quartodoc:
         - plot_annotation
         - plot_spacer
         - plot_layout
+        - inset_element
 
     - title: Options
       desc: |

doc/changelog.qmd

@@ -38,6 +38,9 @@ title: Changelog
   theme(plot_footer_line=element_line(color="black"))
   ```
 
+- Added [](:class:`~plotnine.composition.inset_element`) with which you can insert plot
+  compositions or images into another plot.
+
 ### API Changes
 
 - Removed `geom.to_layer()`, `stat.to_layer()`, `annotate.to_layer()`,