ont docs add css for PLAN keyword

and notes that this that particular css probably should be
configurable so we don't have to push python packages to get new
behavior ... big complexity sigh

nifstd/nifstd_tools/docs.py

@@ -134,7 +134,7 @@ def fixpath(l):
     return '\n'.join(lines) + '\n', title
 
 
-ob_lang_titles = (
+ob_lang_titles = (  # FIXME config (SIGH)
     ('jupyter-python', 'Python'),
     ('sparql', 'SPARQL'),
     ('cypher', 'Cypher'),
@@ -148,8 +148,9 @@ def fixpath(l):
     f"pre.src-{lang}:before  {{ content: '{display}'; }}"
     for lang, display in ob_lang_titles])
 
-todo_colors_css = (
+todo_colors_css = (  # FIXME config (SIGH)
     '.todo.RC {color:black; background-color:khaki;}'
+    '.done.PLAN {color:black; background-color:gray;}'
 )