[CUPS] Update Printer Setup dialog headers.

chrome/app/settings_strings.grdp

Index: chrome/app/settings_strings.grdp
diff --git a/chrome/app/settings_strings.grdp b/chrome/app/settings_strings.grdp
index 57ad06f6b08ab8ea394c71ae93f4f960467a4297..54f715cf10e9788d4e6a7498f8c81ef44285180d 100644
--- a/chrome/app/settings_strings.grdp
+++ b/chrome/app/settings_strings.grdp
@@ -825,10 +825,10 @@
       printer name
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_ADD_PRINTERS_NEARBY_TITLE" desc="Text for the title of the dialog that is used to add nearby printers.">
-      Add printers nearby
+      Add a nearby printer
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_ADD_PRINTERS_MANUALLY_TITLE" desc="Text for the title of the dialog that is used to manually add a printer instead of automatically finding ones nearby.">
-      Add printers manually
+      Add a printer manually
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_DETAILS_TITLE" desc="Text for the title of the Printer Details subpage.">
       Printer details