Improve wording of the title of read receipt list

vector/src/main/java/im/vector/riotx/features/home/room/detail/readreceipts/DisplayReadReceiptsBottomSheet.kt

@@ -66,7 +66,7 @@ class DisplayReadReceiptsBottomSheet : VectorBaseBottomSheetDialogFragment() {
         super.onActivityCreated(savedInstanceState)
         recyclerView.layoutManager = LinearLayoutManager(context, RecyclerView.VERTICAL, false)
         recyclerView.adapter = epoxyController.adapter
-        bottomSheetTitle.text = getString(R.string.read_at)
+        bottomSheetTitle.text = getString(R.string.seen_by)
         epoxyController.setData(displayReadReceiptArgs.readReceipts)
     }
 

vector/src/main/res/values/strings_riotX.xml

@@ -137,4 +137,6 @@
         <item quantity="other">Too many requests have been sent. You can retry in %1$d seconds…</item>
     </plurals>
 
+    <string name="seen_by">Seen by</string>
+
 </resources>