Fix formatting errors in DG

docs/DeveloperGuide.md

@@ -166,8 +166,6 @@ The `Model` component,
 
 <img src="images/BetterModelClassDiagram.png" width="450" />
 
-<div></div>
-
 Multiplicities and other navigabilities are omitted from diagram for simplicity.
 
 </div>
@@ -851,11 +849,14 @@ Cases:
 3. `availability/NotAvailable` with `animalType/` values set to other values which are NOT `current.Cat`, `current.Dog` or `nil`.
 
 Error message:<br>
-"If fosterer is available, animal type should be 'able.Dog' / 'able.Cat'.</br> 
-If animal type information is not available, it should be inputted as 'nil'.<br> 
-If fosterer is NOT available and is currently fostering, animal type should be 'current.Dog' / 'current.Cat'.<br> 
-If fosterer is currently unable to foster, animal type should be inputted as 'nil'.<br> 
-If availability is 'nil', animal type should be 'nil' too."<br>
+"If fosterer is available, animal type should be 'able.Dog' / 'able.Cat'.
+If animal type information is not available, it should be inputted as 'nil'.<br>
+If fosterer is NOT available and is currently fostering, animal type should be 'current.Dog' / 'current.Cat'.<br>
+If fosterer is currently unable to foster, animal type should be inputted as 'nil'.<br>
+
+<div></div>
+
+If availability is 'nil', animal type should be 'nil' too."
 
 Hence, an enhancement would be to split the error message up to only show when each specific case occur, instead of grouping them
 all together into a single message. This would reduce confusion for the user and provide more convenience as the user is no longer