Fix footnote parsing of footnote content (#536)

Fixes #412 and #493.  First we parse footnote content as
its own document avoid quirks with using li as a parent. Second, we
surround placeholders with STX and ETX to prevent them from interfering
with inline parsing; this is also consistent with how placeholders are
used everywhere else in Python Markdown.

1 files changed, 32 insertions, 0 deletions

diff --git a/tests/extensions/extra/footnote.txt b/tests/extensions/extra/footnote.txt
index f95ff2c..93b5869 100644
--- a/tests/extensions/extra/footnote.txt
+++ b/tests/extensions/extra/footnote.txt
@@ -8,6 +8,10 @@ Duplicate[^b] footnotes[^b] test[^b].
 
 Single after duplicates[^c].
 
+Test emphasis at end of footnote[^d]
+
+Complex footnote content[^e]
+
 [^1]: Footnote that ends with a list:
 
     * item 1
@@ -28,3 +32,31 @@ Nor is third...
 [^a]: 1
 [^b]: 2
 [^c]: 3
+
+[^d]:
+    _emphasis works_
+
+    _emphasis still works_
+
+[^e]: 
+    1.  The top couple half figure, contrary sides and hands across with bottom couple,
+
+        Half figure back on your own sides, and turn partner to places,
+
+        Swing partners with right hands into straight line long-ways, as in a reel, and
+
+        Set,
+
+        Hey and return to places,
+
+        The other three couples do the same.
+
+    2.  Top and bottom couples meet and set,
+
+        Then each gentleman leas the opposite lady to the couple on his left, and set,
+
+        Aach four right and left,
+
+        Swing side couples to places, and turn partners all eight,
+
+        The other two couple o the same.