fix(setup): `sed` documentation

These files escaped being parsed in the setup script, when they really
should have been.

setup.sh

@@ -1,9 +1,15 @@
 #!/usr/bin/sh
+sed "s/$1/$2/g" "colors/$1.lua" > "colors/$2.lua"
+rm "colors/$1.lua"
+
+sed "s/$1/$2/g" "doc/$1.txt" > "doc/$2.txt"
+rm "doc/$1.txt"
+
 mv "lua/$1.lua" "lua/$2.lua"
 
-sed "s/$1/$2/g" "colors/$1.vim" > "colors/$2.vim"
-rm "colors/$1.vim"
+sed "s/$1/$2/g" "README.md" > "README_2.md"
+mv "README_2.md" "README.md"
 
 echo "Run 'set rtp+=$(pwd)' from within Vim to include this folder in your runtime path."
 echo ""
-echo "You must do this before sourcing your colorscheme."
+echo "You must do this before sourcing your colorscheme, unless you are using a plugin manager."