Grammar fixes for docs and comments (#5043)

docs/_developer_onboarding.md

@@ -33,7 +33,7 @@
 
 This doc is a quick introduction about the project and its architecture.
 
-It's aim is to help new developers to understand the overall project and where to start developing.
+Its aim is to help new developers to understand the overall project and where to start developing.
 
 Other useful documentation:
 

docs/notifications.md

@@ -149,7 +149,7 @@ That is why clients are able to **process the push rules client side** to decide
 
 As seen previously, App developers don't directly send a push to the end user's device, they use a Push Provider as intermediary. So technically this intermediary is able to read the content of what is sent.
 
-App developers usually mitigate this by sending a `silent notification`, that is a notification with no identifiable data, or with an encrypted payload. When the push is received the app can then synchronise to it's server in order to generate a local notification.
+App developers usually mitigate this by sending a `silent notification`, that is a notification with no identifiable data, or with an encrypted payload. When the push is received the app can then synchronise to its server in order to generate a local notification.
 
 
 ### Background processing limitations

features/login/impl/src/main/kotlin/io/element/android/features/login/impl/login/LoginHelper.kt

@@ -32,7 +32,7 @@ import javax.inject.Inject
 /**
  * This class is responsible for managing the login flow, including handling OIDC actions and
  * submitting login requests.
- * It's an helper to avoid code duplication. It is used by [OnBoardingPresenter], [ConfirmAccountProviderPresenter]
+ * It's a helper to avoid code duplication. It is used by [OnBoardingPresenter], [ConfirmAccountProviderPresenter]
  * and [ChooseAccountProviderPresenter].
  */
 class LoginHelper @Inject constructor(