md4c-html.h: Fix typo in a comment.
diff --git a/src/md4c-html.h b/src/md4c-html.h
index 1042d29..23d3f73 100644
--- a/src/md4c-html.h
+++ b/src/md4c-html.h
@@ -49,7 +49,7 @@
* Callback process_output() gets called with chunks of HTML output.
* (Typical implementation may just output the bytes to a file or append to
* some buffer).
- * Param userdata is just propgated back to process_output() callback.
+ * Param userdata is just propagated back to process_output() callback.
* Param parser_flags are flags from md4c.h propagated to md_parse().
* Param render_flags is bitmask of MD_HTML_FLAG_xxxx.
*