LdapAttributeSet GetAttribute documentation has conflicting information

[mattj23]

The LdapAttributeSet's GetAttribute method states that if an attribute is not found a null will be returned

LdapAttributeSet.cs, see line 70 and106

However, the actual implementation (line 86 and 154) simply uses the [...] operator on the dictionary base class, which instead throws a KeyNotFoundException when the key is missing (as is also specified in the documentation in lines 83 and 150).

It seems that older versions of this library did return a null value if the key wasn't found, as I discovered this issue through broken code in another project. It would be helpful to clarify in the documentation which the intended behavior is.

[dsbenghe]

The most recent version has the documentation corrected. Reported previously here - #121