Fix a bug with Process.group_leader so IEx.pry properly affects the server leader
Add version of String.slice that accepts a Range
Indent code examples correctly
Fix @spec line
Use if instead of case
Fix documentation on String.split/1

Make the beginning match String.split/3. The "on substrings" bit seemed odd and I liked how String.split/3 phrased it instead.
Merge pull request #1770 from ckrailo/minor_documentation_fix

Fix documentation wording on String.split/1
Merge pull request #1769 from drueck/string-slice-range

Add version of String.slice that accepts a Range
Fix wrong :timer.tc call
Lists are already a literal, they don't require a :[] container