Document that search_path is reported by the server

Commit 28a1121 marked search_path as GUC_REPORT, but failed to
update the relevant places in docs. There are two places listing the GUC
options reported to the client, so update both.

Reported-by: Tom Lane
Discussion: https://postgr.es/m/CAFh8B=k8s7WrcqhafmYhdN1+E5LVzZi_QaYDq8bKvrGJTAhY2Q@mail.gmail.com

Author: tvondra

doc/src/sgml/libpq.sgml

@@ -2643,6 +2643,7 @@ const char *PQparameterStatus(const PGconn *conn, const char *paramName);
         <member><varname>IntervalStyle</varname></member>
         <member><varname>is_superuser</varname></member>
         <member><varname>scram_iterations</varname></member>
+        <member><varname>search_path</varname></member>
         <member><varname>server_encoding</varname></member>
         <member><varname>server_version</varname></member>
         <member><varname>session_authorization</varname></member>
@@ -2652,7 +2653,8 @@ const char *PQparameterStatus(const PGconn *conn, const char *paramName);
        (<varname>default_transaction_read_only</varname> and
        <varname>in_hot_standby</varname> were not reported by releases before
        14; <varname>scram_iterations</varname> was not reported by releases
-       before 16.)
+       before 16; <varname>search_path</varname> was not reported by releases
+       before 18.)
        Note that
        <varname>server_version</varname>,
        <varname>server_encoding</varname> and

doc/src/sgml/protocol.sgml

@@ -1325,6 +1325,7 @@ SELCT 1/0;<!-- this typo is intentional -->
      <member><varname>IntervalStyle</varname></member>
      <member><varname>is_superuser</varname></member>
      <member><varname>scram_iterations</varname></member>
+     <member><varname>search_path</varname></member>
      <member><varname>server_encoding</varname></member>
      <member><varname>server_version</varname></member>
      <member><varname>session_authorization</varname></member>
@@ -1334,7 +1335,8 @@ SELCT 1/0;<!-- this typo is intentional -->
     (<varname>default_transaction_read_only</varname> and
     <varname>in_hot_standby</varname> were not reported by releases before
     14; <varname>scram_iterations</varname> was not reported by releases
-    before 16.)
+    before 16; <varname>search_path</varname> was not reported by releases
+    before 18.)
     Note that
     <varname>server_version</varname>,
     <varname>server_encoding</varname> and