jenv: update README

plugins/jenv/README.md

 # jenv plugin
 
 [jenv](https://www.jenv.be/) is a Java version manager similiar to [rbenv](https://github.com/rbenv/rbenv)
-and [pyenv]|(https://github.com/yyuu/pyenv).
+and [pyenv](https://github.com/yyuu/pyenv).
 
-This plugin initializes jenv and adds provides the jenv_prompt_info function to add Java
+This plugin initializes jenv and provides the `jenv_prompt_info` function to add Java
 version information to prompts.
 
 To use, add `jenv` to your plugins array in your zshrc file:
@@ -11,3 +11,17 @@ To use, add `jenv` to your plugins array in your zshrc file:
 ```zsh
 plugins=(... jenv)
 ```
+
+## Theme example
+
+You can modify your `$PROMPT` or `$RPROMPT` variables to run `jenv_prompt_info`.
+
+For example:
+```
+PROMPT="%~$ "
+RPROMPT='$(jenv_prompt_info)'
+```
+changes your prompt to:
+```
+~/java/project$ ▋                                       oracle64-1.6.0.39
+```