changelog: Update through HEAD.

changelog.md

@@ -20,6 +20,9 @@
 - Support parameter elision in command position (e.g., `$foo ls` where `$foo` is unset or empty)
   [#667]
 
+- Don't consider the filename in «sudo -e /path/to/file» to be a command position
+  [#678]
+
 # Changes in version 0.7.1
 
 - Remove out-of-date information from the 0.7.0 changelog.