fix typo

Author: pgrange

README.adoc

@@ -487,7 +487,7 @@ ps
 hello world
 ```
 
-Be carefull however that your \_ps function is not exported to sub-processes. It means that, depending on how your code under test works, _ps may not be defined in the context where ps will be called. For instance:
+Be carefull however that your _ps function is not exported to sub-processes. It means that, depending on how your code under test works, _ps may not be defined in the context where ps will be called. For instance:
 
 ```bash
 _ps() {