tip for using aliases for the virtual registers r0-r15

docs/source/programming.rst

@@ -150,7 +150,8 @@ you from having to type the fully scoped name everytime you need to access that
 Aliases can be created in any scope except at the module level.
 You can create and use an alias with the ``alias`` statement like so::
 
-    alias  prn = txt.print_ub
+    alias  score   = cx16.r7L        ; 'name' the virtual register
+    alias  prn     = txt.print_ub    ; shorter name for a subroutine elsewhere
     ...
     prn(score)
 

docs/source/syntaxreference.rst

@@ -832,6 +832,8 @@ It is not possible to use floating point arguments or return values in an asmsub
     ``cx16.r0`` .. ``cx16.r15``  (these are memory mapped uword values),
     ``cx16.r0s`` .. ``cx16.r15s``  (these are memory mapped word values),
     and ``L`` / ``H`` variants are also available to directly access the low and high bytes of these.
+    You can use them directly but their name isn't very descriptive, so it may be useful to define
+    an alias for them when using them regularly.
 
 
 Expressions