version: don't use NVIM_VERSION_* directly outside version.c

This avoids recompiles after commiting.

src/nvim/buffer.c

@@ -70,6 +70,7 @@
 #include "nvim/syntax.h"
 #include "nvim/ui.h"
 #include "nvim/undo.h"
+#include "nvim/version.h"
 #include "nvim/window.h"
 #include "nvim/os/os.h"
 #include "nvim/os/time.h"
@@ -4033,8 +4034,6 @@ void do_modelines(int flags)
   --entered;
 }
 
-#include "nvim/version.h"            /* for version number */
-
 /*
  * chk_modeline() - check a single line for a mode string
  * Return FAIL if an error encountered.