doc: fix citation references in modularity doc
Modularity Design doc had replicated references to citatation docs.
@@ -22,8 +22,8 @@ include:
safety standards.
* **Meet functional safety requirements** Functional safety standards explicitly
require a hierarchical structure of modules in software architectural
- design. This applies to any safety integrity level defined in IEC 61508
- [IEC_61508-3]_ and ISO 26262 [ISO_26262-6]_.
+ design. This applies to any safety integrity level defined in
+ [IEC_61508-3]_ and [ISO_26262-6]_.
Principles
**********
