docs(thefuck): add description for enabling the plugin (#9433)

Add a description about adding thefuck to the plugins list

plugins/thefuck/README.md

@@ -2,6 +2,10 @@
 
 [The Fuck](https://github.com/nvbn/thefuck) plugin — magnificent app which corrects your previous console command.
 
+To use it, add thefuck to the plugins array of your zshrc file:
+
+plugins=(... thefuck)
+
 ## Usage
 Press `ESC` twice to correct previous console command.