Spelling updates for library-component-overview.md (SharePoint#3654)

A couple of very simple spelling updates. :)

Author: PopWarner

docs/spfx/library-component-overview.md

@@ -25,4 +25,5 @@ Library components have following characteristics:
 * It is not supported to have other component types included in a solution which contains library component
 * You will need to reference library component type during development time from a package manager or using `npm link` to be able to bundle solutions which are dependent on it
 
-You can reference library component dependency in the SharePoint solution by defining the dependency in the package.json file. When this kind of dependency exists in a solution package, SharePoint will automatically load the dependent component for the page. If library reference is not resolved, that can cause an exception in the component which was refering it.
+You can reference library component dependency in the SharePoint solution by defining the dependency in the package.json file. When this kind of dependency exists in a solution package, SharePoint will automatically load the dependent component for the page. If library reference is not resolved, that can cause an exception in the component which was referring it.
+