fix(docs): fix typo 'ngOnit' (#2211)

Author: Suguru Inatomi

public/docs/ts/latest/guide/lifecycle-hooks.jade

@@ -379,8 +379,8 @@ figure.image-display
 .l-sub-section
   :marked
     Our first opportunity to access those properties is the `ngOnChanges` method which
-    Angular calls before `ngOnit`. But Angular calls `ngOnChanges` many times after that.
-    It only calls `ngOnit` once.
+    Angular calls before `ngOnInit`. But Angular calls `ngOnChanges` many times after that.
+    It only calls `ngOnInit` once.
 :marked
   ### OnDestroy