Update 4 demo ReadMe.txt files

Noted change of name of main demo read me file from Demos/DemoReadMe.html
to Demos/README.md

Author: delphidabbler

Demos/1/ReadMe.txt

@@ -1,3 +1,3 @@
 The StandardDemo program for demonstrates design time use of TPJRegWdwState.
 
-For further information see DemoReadMe.htm in the Demos directory.
+For further information see `README.md` in the `Demos` directory.

Demos/2/ReadMe.txt

@@ -1,4 +1,4 @@
 The StandAloneDemo program demonstrates run-time creation and use of
 TPJWdwState.
 
-For further information see DemoReadMe.htm in the Demos directory.
+For further information see `README.md` in the `Demos` directory.

Demos/3/ReadMe.txt

@@ -1,3 +1,3 @@
 The UserDemo program demonstrates use of the TPJUserWdwState component.
 
-For further information see DemoReadMe.htm in the Demos directory.
+For further information see `README.md` in the `Demos` directory.

Demos/4/ReadMe.txt

@@ -3,4 +3,4 @@ The MDIDemo program demonstrates how to use TPJWdwState with MDI applications.
 Modified by Peter Johnson (DelphiDabbler) from an test application provided by
 Craig Symons.
 
-For further information see DemoReadMe.htm in the Demos directory.
+For further information see `README.md` in the `Demos` directory.