release version 9.0

Problem:    About time to release Vim 9.0.
Solution:   Update the version number everywhere.
diff --git a/runtime/doc/os_risc.txt b/runtime/doc/os_risc.txt
index 18f58d4..92af8cd 100644
--- a/runtime/doc/os_risc.txt
+++ b/runtime/doc/os_risc.txt
@@ -1,4 +1,4 @@
-*os_risc.txt*   For Vim version 8.2.  Last change: 2011 May 10
+*os_risc.txt*   For Vim version 9.0.  Last change: 2011 May 10
 
 
 		  VIM REFERENCE MANUAL    by Thomas Leonard