README.md: documentation nitpick for mpd

Author: Mic92

README.md

@@ -335,8 +335,8 @@ Supported platforms: platform independent (required tools: `curl`).
 
 * Argument: an array including password, hostname and port in that order. `nil`
   fields will be fallen back to default (`localhost:6600` without password).
-* Returns a table with string keys: `${volume}`, `${bitrate}`, `${elapsed}`,
-  `${duration}` (in seconds), `${Elapsed}`, `${Duration}` (in [hh:]mm:ss),
+* Returns a table with string keys: `${volume}`, `${bitrate}`, `${elapsed}` (in seconds),
+  `${duration}` (in seconds), `${Elapsed}` (formatted as [hh:]mm:ss), `${Duration}` (formatted as [hh:]mm:ss),
   `${random}`, `${repeat}`, `${state}`, `${Artist}`, `${Title}`, `${Album}`,
   `${Genre}` and optionally `${Name}` and `${file}`.