Cleanup some IEEE references

src/V3Assert.cpp

@@ -154,7 +154,7 @@ private:
             if (m_procedurep) {
                 // To support this need queue of asserts to activate
                 nodep->v3error("Unsupported: Procedural concurrent assertion with"
-                               " clocking event inside always (IEEE 1800-2917 16.14.6)");
+                               " clocking event inside always (IEEE 1800-2017 16.14.6)");
             }
         }
         //