changelog: Fix markup.

changelog.md

@@ -20,13 +20,13 @@
 - 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
+- Don't consider the filename in `sudo -e /path/to/file` to be a command position
   [#678]
 
 - Don't look up absolute directory names in $cdpath
   [2cc2583f8f12, part of #669]
 
-- Fix "exec 2>&1;" being highlighted as an error.
+- Fix `exec 2>&1;` being highlighted as an error.
   [#676]
 
 # Changes in version 0.7.1