Update documentation for SA1308 to also mention prefix "t_"

#3695

Author: bjornhellander

documentation/SA1308.md

@@ -17,11 +17,11 @@
 
 ## Cause
 
-A field name in C# is prefixed with *m_* or *s_*.
+A field name in C# is prefixed with *m_*, *s_*, or *t_*.
 
 ## Rule description
 
-A violation of this rule occurs when a field name is prefixed by *m_* or *s_*.
+A violation of this rule occurs when a field name is prefixed by *m_*, *s_*, or *t_*.
 
 By default, StyleCop disallows the use of underscores, *m_*, etc., to mark local class fields, in favor of the 'this.' prefix. The advantage of using 'this.' is that it applies equally to all element types including methods, properties, etc., and not just fields, making all calls to class members instantly recognizable, regardless of which editor is being used to view the code. Another advantage is that it creates a quick, recognizable differentiation between instance members and static members, which will not be prefixed.