markdown head title needs space

This closes #2090
diff --git a/doc/specs/HeaderFormat.md b/doc/specs/HeaderFormat.md
index 42ec7ae..0456f1e 100644
--- a/doc/specs/HeaderFormat.md
+++ b/doc/specs/HeaderFormat.md
@@ -74,7 +74,7 @@
                           data.
 
 
-###Info IDs:
+### Info IDs:
 
     INFO_KEYVALUE 0x01 - varint32 number of headers.
                        - key/value pairs of varstrings (varint16 length plus