Updated vim plugins

sources_non_forked/vim-markdown/test/setextoatx.vader

@@ -0,0 +1,48 @@
+Given markdown;
+# a
+
+a
+=
+
+## b
+
+b
+-
+
+Execute (SetexToAtx):
+  :SetexToAtx
+
+Expect (convert setex-style headings to atx):
+  # a
+
+  # a
+
+  ## b
+
+  ## b
+
+Given markdown;
+a
+=
+
+b
+=
+
+c
+-
+
+d
+-
+
+Execute (SetexToAtx with range):
+  :1,8SetexToAtx
+
+Expect (only convert setex headings in original range):
+  # a
+
+  # b
+
+  ## c
+
+  d
+  -