Update contritutions section (Mehmet)

Author: pedritomelenas

doc/contributions.xml

@@ -294,7 +294,13 @@ Mehmet Yeşil contributed to the following functions.
   <P/>
   <Ref Prop="HookLengths"/>,
   <P/>
-  <Ref Prop="DualNumericalSet"/>.
+  <Ref Prop="DualNumericalSet"/>,
+  <P/>
+  <Ref Prop="BondedSum"/>,
+  <P/>
+  <Ref Prop="CojointSum"/>,
+  <P/>
+  <Ref Prop="EndToEndSum"/>.
 
 
 </Section>