release version 9.0

Problem:    About time to release Vim 9.0.
Solution:   Update the version number everywhere.
diff --git a/src/GvimExt/GvimExt.reg b/src/GvimExt/GvimExt.reg
index 129ce6e..d9ebff8 100644
--- a/src/GvimExt/GvimExt.reg
+++ b/src/GvimExt/GvimExt.reg
@@ -15,6 +15,6 @@
 [HKEY_LOCAL_MACHINE\Software\Vim\Gvim]
    "path"="gvim.exe"
 
-[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall\Vim 8.2]
-   "DisplayName"="Vim 8.2: Edit with Vim popup menu entry"
+[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall\Vim 9.0]
+   "DisplayName"="Vim 9.0: Edit with Vim popup menu entry"
    "UninstallString"="uninstall.exe"