Spelling correction (SharePoint#4532)

Update the "Incons" to "Icons" in the title "Updated way to use icons (after SPFx 1.8.2)"

Author: muges01

docs/spfx/office-ui-fabric-integration.md

@@ -293,7 +293,7 @@ There are changes on how to use Office UI Fabric icons in the rendering of the S
 <i className={css('ms-Icon', 'ms-Icon--RecurringEvent')}></i>
 ```
 
-### Updated way to use incons (after SPFx 1.8.2)
+### Updated way to use icons (after SPFx 1.8.2)
 
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