Add notes.

notes/blog_posts/org_mode/notes.org

@@ -6,6 +6,10 @@ They have different precedent despite identical values
 ** Invisible, non-typeable escape character
 ** Why not use the invisible escape character for the special case of entities
 entities use ={}= to escape the end of an entity but the invisible non-typeable escape character used everywhere else would have worked here too.
+** So many different escape characters
+- invisible escape character in general
+- ={}= at the end of an entity
+- comma at the start of a line
 * Comparison to other formats
 ** Markdown
 *** Critique of markdown