chore: fix typo (#2422)

Initially, it was giving the same hint as the problem above, that asked for the distance driven. This wasn't hinting that we need an extra, separate field to track the battery charge, as demonstrated by many popular solutions.

Author: lapiselazul

exercises/concept/jedliks-toys/.docs/hints.md

@@ -14,8 +14,8 @@
 
 ## 3. Display the battery percentage
 
-- Keep track of the distance driven in a [field][fields].
-- Initialize the field to a specific value to correspond to the initial battery charge.
+- Keep track of the initial battery charge in a [field][fields].
+- Initialize the field to a specific value that corresponds to the expected initial battery charge.
 - Consider what visibility to use for the field (does it need to be used outside the class?).
 - Consider using [string interpolation][string-interpolation] to format the string to return.