[javascript] Make list consistent, put Earth in proper order (#710)

Sorry, this was driving me nuts.

Author: joshgoebel

exercises/space-age/README.md

@@ -2,9 +2,9 @@
 
 Given an age in seconds, calculate how old someone would be on:
 
-   - Earth: orbital period 365.25 Earth days, or 31557600 seconds
    - Mercury: orbital period 0.2408467 Earth years
    - Venus: orbital period 0.61519726 Earth years
+   - Earth: orbital period 1.0 Earth years, 365.25 Earth days, or 31,557,600 seconds
    - Mars: orbital period 1.8808158 Earth years
    - Jupiter: orbital period 11.862615 Earth years
    - Saturn: orbital period 29.447498 Earth years