README edits

Updated the names of the (preferred) cheat-related environment
variables, which have been changed in recent versions.

README.md

@@ -83,37 +83,37 @@ with your [dotfiles][].
 Configuring
 -----------
 
-### Setting a DEFAULT_CHEAT_DIR ###
+### Setting a CHEAT_DEFAULT_DIR ###
 Personal cheatsheets are saved in the `~/.cheat` directory by default, but you
-can specify a different default by exporting a `DEFAULT_CHEAT_DIR` environment
+can specify a different default by exporting a `CHEAT_DEFAULT_DIR` environment
 variable:
 
 ```sh
-export DEFAULT_CHEAT_DIR='/path/to/my/cheats'
+export CHEAT_DEFAULT_DIR='/path/to/my/cheats'
 ```
 
-### Setting a CHEATPATH ###
+### Setting a CHEAT_PATH ###
 You can additionally instruct `cheat` to look for cheatsheets in other
-directories by exporting a `CHEATPATH` environment variable:
+directories by exporting a `CHEAT_PATH` environment variable:
 
 ```sh
-export CHEATPATH='/path/to/my/cheats'
+export CHEAT_PATH='/path/to/my/cheats'
 ```
 
-You may, of course, append multiple directories to your `CHEATPATH`:
+You may, of course, append multiple directories to your `CHEAT_PATH`:
 
 ```sh
-export CHEATPATH="$CHEATPATH:/path/to/more/cheats"
+export CHEAT_PATH="$CHEAT_PATH:/path/to/more/cheats"
 ```
 
-You may view which directories are on your `CHEATPATH` with `cheat -d`.
+You may view which directories are on your `CHEAT_PATH` with `cheat -d`.
 
 ### Enabling Syntax Highlighting ###
 `cheat` can optionally apply syntax highlighting to your cheatsheets. To
-enable syntax highlighting, export a `CHEATCOLORS` environment variable:
+enable syntax highlighting, export a `CHEAT_COLORS` environment variable:
 
 ```sh
-export CHEATCOLORS=true
+export CHEAT_COLORS=true
 ```
 
 Note that [pygments][] must be installed on your system for this to work.