Update models-usage.md

Clarify the phrases, "Notice that the accessor is singular/plural" - which may be confusing as the term, "accessor", typically refers to code

docs/docs/models-usage.md

@@ -443,7 +443,7 @@ Task.findAll({ include: [ User ] }).then(function(tasks) {
 })
 })
 ```
 ```
 
 
-Notice that the accessor is singular as the association is one-to-something.
+Notice that the accessor (the `User` property in the resulting instance) is singular because the association is one-to-something.
 
 
 Next thing: Loading of data with many-to-something associations!
 Next thing: Loading of data with many-to-something associations!
 
 
@@ -469,7 +469,8 @@ User.findAll({ include: [ Task ] }).then(function(users) {
 })
 })
 ```
 ```
 
 
-Notice that the accessor is plural. This is because the association is many-to-something.
+Notice that the accessor (the `Tasks` property in the resulting instance) is plural because the association is many-to-something.
+
 
 
 If an association is aliased (using the `as` option), you must specify this alias when including the model. Notice how the user's `Tool`s are aliased as `Instruments` above. In order to get that right you have to specify the model you want to load, as well as the alias:
 If an association is aliased (using the `as` option), you must specify this alias when including the model. Notice how the user's `Tool`s are aliased as `Instruments` above. In order to get that right you have to specify the model you want to load, as well as the alias: