Add recipe 19 to recipes listing with filter keywords

Author: sadielbartholomew

docs/source/recipes/recipe_list.txt

@@ -27,4 +27,6 @@ plot_13_recipe.html#sphx-glr-recipes-plot-13-recipe-py
 plot_14_recipe.html#sphx-glr-recipes-plot-14-recipe-py
 <div class="sphx-glr-thumbcontainer subspace collapse contourmap" tooltip="Subspace, Collapse, Contourmap">
 plot_15_recipe.html#sphx-glr-recipes-plot-15-recipe-py
-<div class="sphx-glr-thumbcontainer histogram subspace" tooltip="Histogram, Subspace">
+<div class="sphx-glr-thumbcontainer histogram subspace" tooltip="Histogram, Subspace">
+plot_19_recipe.html#sphx-glr-recipes-plot-19-recipe-py
+<div class="sphx-glr-thumbcontainer collapse subspace subplot lineplot" tooltip="Collapse, Subspace, Subplot, Lineplot">