Remove unused UShowPrefsPageAction unit from project

Author: delphidabbler

Src/CodeSnip.dpr

@@ -313,7 +313,6 @@ uses
   USelectionIOMgr in 'USelectionIOMgr.pas',
   USettings in 'USettings.pas',
   UShowCaseCtrl in 'UShowCaseCtrl.pas',
-  UShowPrefsPageAction in 'UShowPrefsPageAction.pas',
   USimpleDispatch in 'USimpleDispatch.pas',
   USingleton in 'USingleton.pas',
   USnipKindListAdapter in 'USnipKindListAdapter.pas',

Src/CodeSnip.dproj

@@ -510,7 +510,6 @@
 			<DCCReference Include="USelectionIOMgr.pas"/>
 			<DCCReference Include="USettings.pas"/>
 			<DCCReference Include="UShowCaseCtrl.pas"/>
-			<DCCReference Include="UShowPrefsPageAction.pas"/>
 			<DCCReference Include="USimpleDispatch.pas"/>
 			<DCCReference Include="USingleton.pas"/>
 			<DCCReference Include="USnipKindListAdapter.pas"/>