doc: Clarify required options for each action in pg_recvlogical.

Each pg_recvlogical action requires specific options. For example,
--slot, --dbname, and --file must be specified with the --start action.
Previously, the documentation did not clearly outline these requirements.

This commit updates the documentation to explicitly state
the necessary options for each action.

Author: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Co-authored-by: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Vignesh C <vignesh21@gmail.com>
Reviewed-by: David G. Johnston <david.g.johnston@gmail.com>
Discussion: https://postgr.es/m/OSCPR01MB14966930B4357BAE8C9D68A8AF5C72@OSCPR01MB14966.jpnprd01.prod.outlook.com

doc/src/sgml/ref/pg_recvlogical.sgml

@@ -73,6 +73,11 @@ PostgreSQL documentation
         by <option>--dbname</option>.
        </para>
 
+       <para>
+        The <option>--slot</option> and <option>--dbname</option> are required
+        for this action.
+       </para>
+
        <para>
         The <option>--two-phase</option> can be specified with
         <option>--create-slot</option> to enable decoding of prepared transactions.
@@ -87,6 +92,10 @@ PostgreSQL documentation
         Drop the replication slot with the name specified
         by <option>--slot</option>, then exit.
        </para>
+
+       <para>
+        The <option>--slot</option> is required for this action.
+       </para>
       </listitem>
      </varlistentry>
 
@@ -101,6 +110,11 @@ PostgreSQL documentation
         <option>--no-loop</option> is specified.
        </para>
 
+       <para>
+        The <option>--slot</option> and <option>--dbname</option>,
+        <option>--file</option> are required for this action.
+       </para>
+
        <para>
         The stream format is determined by the output plugin specified when
         the slot was created.
@@ -159,6 +173,9 @@ PostgreSQL documentation
         Write received and decoded transaction data into this
         file. Use <literal>-</literal> for <systemitem>stdout</systemitem>.
        </para>
+       <para>
+        This parameter is required for <option>--start</option>.
+       </para>
       </listitem>
      </varlistentry>
 
@@ -265,6 +282,9 @@ PostgreSQL documentation
         mode, create the slot with this name. In <option>--drop-slot</option>
         mode, delete the slot with this name.
        </para>
+       <para>
+        This parameter is required for any of actions.
+       </para>
       </listitem>
      </varlistentry>
 
@@ -305,7 +325,11 @@ PostgreSQL documentation
          The <replaceable>dbname</replaceable> can be a <link
          linkend="libpq-connstring">connection string</link>.  If so,
          connection string parameters will override any conflicting
-         command line options.  Defaults to the user name.
+         command line options.
+        </para>
+        <para>
+         This parameter is required for <option>--create-slot</option>
+         and <option>--start</option>.
         </para>
        </listitem>
       </varlistentry>