Merge pull request #111 from timgalebach/patch-1

Fix typo in three_principles_revised.md

Author: davidmarne

Diff for: doc/introduction/three_principles_revised.md

@@ -22,4 +22,4 @@ To specify how the state tree is transformed by actions, you write reducers.
 
 In redux.js and redux.dart, reducers are just pure functions that take the previous state and an action, and return the next state. You are required to return new state objects, instead of mutating the previous state. This is where built_redux differs.
 
-With built_redux your reducer functions are passed a referenece to a builder for your state object and you apply any changes to that builder. This means your reducers are actually void functions. This is because, behind the scenes, built_redux calls `.toBuilder()` on your state object once, and passes you a reference to the builder to mutate so you do not have to call `.toBuilder()` or `.rebuild(updates)` on your state objects manually.
+With built_redux your reducer functions are passed a reference to a builder for your state object and you apply any changes to that builder. This means your reducers are actually void functions. This is because, behind the scenes, built_redux calls `.toBuilder()` on your state object once, and passes you a reference to the builder to mutate so you do not have to call `.toBuilder()` or `.rebuild(updates)` on your state objects manually.