Update 556-data-isdir.markdown

Author: Joe7M

_build/reference/556-data-isdir.markdown

@@ -1,7 +1,11 @@
 # ISDIR
 
-> ISDIR (x)
+> b = ISDIR (dir)
 
-Returns true if x is a directory.
+Returns true if the string `dir` is a directory.
 
+```
+print IsDir("C:\users")        ' Output 1 on Windows, otherwise 0
+print IsDir("\home")           ' Output 1 on Linux, otherwise 0
+```