[readme] bash shell integration: Amended example to call cd when booting a terminal (previously only called on cd).

It means that works with for example VS Code's integrated terminal.

README.md

@@ -514,6 +514,7 @@ cdnvm(){
     fi
 }
 alias cd='cdnvm'
+cd $PWD
 ```
 
 This alias would search 'up' from your current directory in order to detect a `.nvmrc` file. If it finds it, it will switch to that version; if not, it will use the default version.