Add more description to @property getters and setters.

objective-c.html.markdown

@@ -233,6 +233,9 @@ int main (int argc, const char * argv[])
 @property int count;
 @property (copy) NSString *name; // Copy the object during assignment.
 @property (readonly) id data;    // Declare only a getter method.
+// To access variable in implementation file, use '_' followed by variable name:
+_count = 5;
+NSLog("%@", _count); // => prints 5 to console
 
 // Methods
 +/- (return type)methodSignature:(Parameter Type *)parameterName;