Polish plugin placeholder strings.

components/components_strings.grd

 <?xml version="1.0" encoding="utf-8"?>
 
 <grit latest_public_release="0" current_release="1"
       output_all_resource_defines="false" source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/components_strings.h" type="rc_header">
       <emit emit_type='prepend'></emit>
     </output>
     <output filename="components_strings_am.pak" type="data_package" lang="am" />
     <output filename="components_strings_ar.pak" type="data_package" lang="ar" />
@@ skipping 226 matching lines @@
           Not now
         </message>
       </if>
       <if expr="use_titlecase">
         <message name="IDS_NOT_NOW" desc="In Title Case: Used on a button that avoids taking a suggested action.  The action will likely be suggested again or automatically taken later.">
           Not Now
         </message>
       </if>
 
       <message name="IDS_PLUGIN_NOT_SUPPORTED" desc="The placeholder text for an unsupported plugin.">
-        This plugin is not supported.
+        This plugin is not supported
       </message>
       <if expr="not is_android">
         <if expr="not use_titlecase">
           <message name="IDS_PRINT" desc="The text label of the Print... menu item. Opens a dialog box to select print settings">
             &amp;Print...
           </message>
         </if>
         <if expr="use_titlecase">
           <message name="IDS_PRINT" desc="In Title Case: The text label of the Print... menu item. Opens a dialog box to select print settings">
             &amp;Print...
@@ skipping 38 matching lines @@
         Your connection to this site is not private.
       </message>
 
       <!-- Advanced Section Titles -->
       <message name="IDS_OPTIONS_ADVANCED_SECTION_TITLE_PRIVACY">
         Privacy
       </message>
     </messages>
   </release>
 </grit>