patch 8.2.4669: in compiled code len('string') is not inlined

Problem:    In compiled code len('string') is not inlined.
Solution:   Compute the length at compile time if possible. (closes #10065)

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4669,
 /**/
     4668,
 /**/