Slight correction to <str>.strip descriptions

Removes <chars> (or whitespace) from start of <str> up to the first
non-<chars> and from the end of <str> up to the last non-<chars>.

https://docs.python.org/3/library/stdtypes.html?highlight=strip#str.strip

README.md

@@ -226,8 +226,8 @@ from numbers import Number, Integral, Real, Rational, Complex
 String
 ------
 ```python
-<str>  = <str>.strip()           # Strips all whitespace characters.
-<str>  = <str>.strip('<chars>')  # Strips all passed characters.
+<str>  = <str>.strip()           # Strips all whitespace characters from start and end.
+<str>  = <str>.strip('<chars>')  # Strips all passed characters from start and end.
 ```
 
 ```python