Add IDSymbol for pullrequest Bitmap

src/GitHub.InlineReviews/InlineReviewsPackage.vsct

@@ -75,7 +75,7 @@
       </Button>
     </Buttons>
     <Bitmaps>
-      <Bitmap guid="guidImages" href="Resources\PullRequestFilterCommand.png" usedList="bmpPic1, bmpPic2, bmpPicSearch, bmpPicX, bmpPicArrows, bmpPicStrikethrough"/>
+      <Bitmap guid="guidImages" href="Resources\PullRequestFilterCommand.png" usedList="pullrequest"/>
     </Bitmaps>
   </Commands>
   <KeyBindings>
@@ -99,12 +99,7 @@
     </GuidSymbol>
 
     <GuidSymbol name="guidImages" value="{775aa523-6c52-4c11-9c28-823c99d15613}" >
-      <IDSymbol name="bmpPic1" value="1" />
-      <IDSymbol name="bmpPic2" value="2" />
-      <IDSymbol name="bmpPicSearch" value="3" />
-      <IDSymbol name="bmpPicX" value="4" />
-      <IDSymbol name="bmpPicArrows" value="5" />
-      <IDSymbol name="bmpPicStrikethrough" value="6" />
+      <IDSymbol name="pullrequest" value="1" />
     </GuidSymbol>
   </Symbols>
 </CommandTable>