docs: remove redundant whitespaces and fix minor typos (#33422)

PR Close #33422

aio/content/guide/dependency-injection-navtree.md

@@ -233,7 +233,7 @@ A component that could serve as a parent *should* implement the class interface
 
 
 
-Doing so adds clarity to the code.  But it's not technically necessary.
+Doing so adds clarity to the code. But it's not technically necessary.
 Although `AlexComponent` has a `name` property, as required by its `Base` class,
 its class signature doesn't mention `Parent`.
 
@@ -283,4 +283,3 @@ Here's a revised version that defaults to `parent` but also accepts an optional
 And here's how you could use it with a different parent type.
 
 <code-example path="dependency-injection-in-action/src/app/parent-finder.component.ts" region="beth-providers" header="dependency-injection-in-action/src/app/parent-finder.component.ts"></code-example>
-