Replace relative link with web link

In order to fix doxygen error.

Author: thomasspriggs

doc/architectural/central-data-structures.md

@@ -111,7 +111,7 @@ A  goto program  is a sequence of GOTO instructions (`goto_instructiont`). For
 details of the `goto_programt` class itself see the documentation in
 [`goto_program.h`](../../src/goto-programs/goto_program.h). For further details
 of the life cycle of goto programs see
-[`src/goto-programs/README.md`](../../src/goto-programs/README.md).
+[`src/goto-programs/README.md`](https://github.com/diffblue/cbmc/blob/develop/src/goto-programs/README.md).
 
 An instruction (`goto_instructiont`) is a triple (an element with three subcomponents),
 describing a GOTO level instruction with the following 3 component subtypes,