Fix table of contents links' case

Plugins.md

@@ -36,7 +36,7 @@ Below is a list of bundled plugins
 - [chruby](#chruby)
 - [chucknorris](#chucknorris)
 - [command-not-found](#command-not-found)
-- [Composer](#Composer)
+- [Composer](#composer)
 - [cloudapp](#cloudapp)
 - [coffee](#coffee)
 - [common-aliases](#common-aliases)
@@ -51,7 +51,7 @@ Below is a list of bundled plugins
 - [encode64](#encode64)
 - [fabric](#fabric)
 - [fbterm](#fbterm)
-- [Forklift](#Forklift)
+- [Forklift](#forklift)
 - [fasd](#fasd)
 - [gas](#gas)
 - [geeknote](#geeknote)