Update regex examples to clarify treatment of spaces (#149)
Update regex examples to clarify treatment of spaces (#149)

```
# Double quotes contain the resulting values (to signify whitespace)
DOT_ENV=dotenv # => "dotenv"
#DOTENV=dotenv # => no match
DOT_ENV= asdf asf # => " asdf asf "
DOTENV='dot env' # => "dot env"
DOTENV="dot env" # => "dot env"
DOT_ENV='dotenv' # => "dotenv"
DOT_ENV="DotEnv" # => "DotEnv"
DOTENV="Dot\nEnv" # => "Dot\nEnv"
DOTENV="{"Dot":"Env"}" # => "{\"Dot\":\"Env\"}"
export DOTENV="dotenv" # => "dotenv"
DOTENV ="dot env" # => no match
DOTENV= "dot env" # => "dot env"
DOTENV = "dot env" # => no match
```
luggit/react-native-config,luggit/react-native-config,luggit/react-native-config,luggg/react-native-config,luggg/react-native-config,luggit/react-native-config,luggit/react-native-config,luggg/react-native-config,luggit/react-native-config