Added reply self hint text

app/src/main/res/layout/fragment_identity.xml

@@ -556,6 +556,16 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/cbPrimary" />
 
+        <eu.faircode.email.FixedTextView
+            android:id="@+id/tvSelfHint"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/title_identity_self_hint"
+            android:textAppearance="@style/TextAppearance.AppCompat.Small"
+            android:textStyle="italic"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/cbSelf" />
+
         <CheckBox
             android:id="@+id/cbSenderExtra"
             android:layout_width="wrap_content"
@@ -563,7 +573,7 @@
             android:layout_marginTop="12dp"
             android:text="@string/title_advanced_sender"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toBottomOf="@id/cbSelf" />
+            app:layout_constraintTop_toBottomOf="@id/tvSelfHint" />
 
         <eu.faircode.email.FixedTextView
             android:id="@+id/tvSenderExtra"

app/src/main/res/values/strings.xml

@@ -640,6 +640,7 @@
     <string name="title_identity_max_size">Maximum message size (MB)</string>
     <string name="title_identity_receipt">Request delivery/read receipt by default</string>
     <string name="title_identity_use_ip_hint">In case of \'invalid greeting\', \'requires valid address\' or a similar error, try to change this setting</string>
+    <string name="title_identity_self_hint">Also prevents you from replying to yourself</string>
     <string name="title_optional">Optional</string>
     <string name="title_recommended">Recommended</string>
     <string name="title_account_linked">Linked account</string>