[libc] Update some implementation status for search.h (#148414)

- `VISIT` was implemented in
#132746.
- `lsearch` was implemented in
#131431.

At first, I thought this would be updated automatically, but it seems
that the header status needs to be added manually.

Author: c8ef

libc/docs/headers/search.rst

@@ -29,7 +29,7 @@ Type Name                    Available
 ============================ =========
 ACTION                       |check|
 ENTRY                        |check|
-VISIT
+VISIT                        |check|
 ============================ =========
 
 POSIX Standard Functions
@@ -43,7 +43,7 @@ hdestroy                     |check|
 hsearch                      |check|
 insque                       |check|
 lfind                        |check|
-lsearch
+lsearch                      |check|
 remque                       |check|
 tdelete
 tfind