patch 8.2.4545: MS-Windows: the installed icon is low resolution

Problem:    MS-Windows: the installed icon is low resolution.
Solution:   Use a better icon.  Install vim.ico. (Christian Brabandt,
            closes #9931, closes #9930)
diff --git a/nsis/gvim.nsi b/nsis/gvim.nsi
index c32a886..f9b1790 100644
--- a/nsis/gvim.nsi
+++ b/nsis/gvim.nsi
@@ -403,6 +403,9 @@
 	SetOutPath $0\autoload\xml
 	File ${VIMRT}\autoload\xml\*.*
 
+	SetOutPath $0\bitmaps
+	File ${VIMSRC}\vim.ico
+
 	SetOutPath $0\syntax
 	File ${VIMRT}\syntax\*.*