[gdb/guile] Fix doc string for value-optimized-out?

In gdb/guile/scm-value.c, I noticed in the value_functions array initializer:
...
  { "value-optimized-out?", 1, 0, 0,
    as_a_scm_t_subr (gdbscm_value_optimized_out_p),
    "\
Return #t if the value has been optimizd out." },
...
There's a typo in the doc string.

Fix this by using "optimized".

Reviewed-By: Tom Tromey <tom@tromey.com>
diff --git a/gdb/guile/scm-value.c b/gdb/guile/scm-value.c
index 32a9539..6f325db 100644
--- a/gdb/guile/scm-value.c
+++ b/gdb/guile/scm-value.c
@@ -1358,7 +1358,7 @@ Typically this is used to convert numbers and strings to\n\
   { "value-optimized-out?", 1, 0, 0,
     as_a_scm_t_subr (gdbscm_value_optimized_out_p),
     "\
-Return #t if the value has been optimizd out." },
+Return #t if the value has been optimized out." },
 
   { "value-address", 1, 0, 0, as_a_scm_t_subr (gdbscm_value_address),
     "\