Added new Export keyword for documentation.

blitz.mod/blitz.bmx

@@ -854,6 +854,11 @@ bbdoc: Denote a field as read only, where the value may only be set in its decla
 keyword: "ReadOnly"
 End Rem
 
+Rem
+bbdoc: Denote a function for export to a shared library. The generated function name will not be mangled.
+keyword: "Export"
+End Rem
+
 Rem
 bbdoc: Specify constraints on the types that can be used as arguments for a type parameter defined in a generic declaration
 keyword: "Where"