Add CURLM error constant version availability info (#4031)

Co-authored-by: haszi <haszika80@gmail.com>

reference/curl/constants_curl_multi.xml

@@ -9,7 +9,7 @@
   <listitem>
    <simpara>
     An easy handle already added to a multi handle was attempted to get added a second time.
-    Available as of cURL 7.32.1
+    Available as of cURL 7.32.1.
    </simpara>
   </listitem>
  </varlistentry>
@@ -21,6 +21,7 @@
   <listitem>
    <simpara>
     An easy handle was not good/valid. It could mean that it is not an easy handle at all, or possibly that the handle already is in use by this or another multi handle.
+    Available as of cURL 7.9.6.
    </simpara>
   </listitem>
  </varlistentry>
@@ -32,6 +33,7 @@
   <listitem>
    <simpara>
     The passed-in handle is not a valid multi handle.
+    Available as of cURL 7.9.6.
    </simpara>
   </listitem>
  </varlistentry>
@@ -46,6 +48,7 @@
     Before cURL 7.20.0, this status could be returned by
     <function>curl_multi_exec</function> when <function>curl_multi_select</function>
     or a similar function was called before it returned any other constant.
+    Available as of cURL 7.9.6.
    </simpara>
   </listitem>
  </varlistentry>
@@ -57,6 +60,7 @@
   <listitem>
    <simpara>
     Internal <literal>libcurl</literal> error.
+    Available as of cURL 7.9.6.
    </simpara>
   </listitem>
  </varlistentry>
@@ -68,6 +72,7 @@
   <listitem>
    <simpara>
     No errors.
+    Available as of cURL 7.9.6.
    </simpara>
   </listitem>
  </varlistentry>
@@ -79,6 +84,7 @@
   <listitem>
    <simpara>
     Ran out of memory while processing multi handles.
+    Available as of cURL 7.9.6.
    </simpara>
   </listitem>
  </varlistentry>