Fix the inconsistent and wrong claims that the option value in CREATE

FOREIGN DATA WRAPPER/SERVER/USER MAPPING is optional.

doc/src/sgml/ref/create_foreign_data_wrapper.sgml

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-$PostgreSQL: pgsql/doc/src/sgml/ref/create_foreign_data_wrapper.sgml,v 1.2 2009/02/24 10:06:32 petere Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_foreign_data_wrapper.sgml,v 1.3 2009/02/27 07:20:00 petere Exp $
 PostgreSQL documentation
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@@ -82,7 +82,7 @@ CREATE FOREIGN DATA WRAPPER <replaceable class="parameter">name</replaceable>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>OPTIONS ( <replaceable class="PARAMETER">option</replaceable> ['<replaceable class="PARAMETER">value</replaceable>'] [, ... ] )</literal></term>
+    <term><literal>OPTIONS ( <replaceable class="PARAMETER">option</replaceable> '<replaceable class="PARAMETER">value</replaceable>' [, ... ] )</literal></term>
     <listitem>
      <para>
       This clause specifies options for the new foreign-data wrapper.

doc/src/sgml/ref/create_server.sgml

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-$PostgreSQL: pgsql/doc/src/sgml/ref/create_server.sgml,v 1.2 2009/01/17 04:29:00 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_server.sgml,v 1.3 2009/02/27 07:20:00 petere Exp $
 PostgreSQL documentation
 -->
 
@@ -85,7 +85,7 @@ CREATE SERVER <replaceable class="parameter">servername</replaceable> [ TYPE 'se
    </varlistentry>
 
    <varlistentry>
-    <term><literal>OPTIONS ( <replaceable class="PARAMETER">option</replaceable> ['<replaceable class="PARAMETER">value</replaceable>'] [, ... ] )</literal></term>
+    <term><literal>OPTIONS ( <replaceable class="PARAMETER">option</replaceable> '<replaceable class="PARAMETER">value</replaceable>' [, ... ] )</literal></term>
     <listitem>
      <para>
       This clause specifies the options for the server.  The options

doc/src/sgml/ref/create_user_mapping.sgml

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-$PostgreSQL: pgsql/doc/src/sgml/ref/create_user_mapping.sgml,v 1.3 2009/01/20 09:10:20 petere Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_user_mapping.sgml,v 1.4 2009/02/27 07:20:00 petere Exp $
 PostgreSQL documentation
 -->
 
@@ -69,7 +69,7 @@ CREATE USER MAPPING FOR { <replaceable class="parameter">username</replaceable>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>OPTIONS ( <replaceable class="PARAMETER">option</replaceable> ['<replaceable class="PARAMETER">value</replaceable>'] [, ... ] )</literal></term>
+    <term><literal>OPTIONS ( <replaceable class="PARAMETER">option</replaceable> '<replaceable class="PARAMETER">value</replaceable>' [, ... ] )</literal></term>
     <listitem>
      <para>
       This clause specifies the options of the user mapping.  The