Clarify description of use_parentheses

Backslashes are different from slashes.

I was looking for this option so I searched for "backslash", found no hits, and assumed it didn't exist.  I only found it later by accident.

docs/configuration/options.md

@@ -762,7 +762,7 @@ Balances wrapping to produce the most consistent line length possible
 
 ## Use Parentheses
 
-Use parentheses for line continuation on length limit instead of slashes. **NOTE**: This is separate from wrap modes, and only affects how individual lines that  are too long get continued, not sections of multiple imports.
+Use parentheses for line continuation on length limit instead of backslashes. **NOTE**: This is separate from wrap modes, and only affects how individual lines that  are too long get continued, not sections of multiple imports.
 
 **Type:** Bool  
 **Default:** `False`