(Network insight) extend help text, not supported when using RAM disk. closes...

(Network insight) extend help text, not supported when using RAM disk. closes https://github.com/opnsense/core/issues/999

(cherry picked from commit dc3ad76b)

src/opnsense/mvc/app/controllers/OPNsense/Diagnostics/forms/netflow_capture.xml

@@ -19,7 +19,7 @@
         <id>netflow.collect.enable</id>
         <label>Capture local</label>
         <type>checkbox</type>
-        <help>Collect NetFlow data on this firewall, this will automatically append localhost as NetFlow target.</help>
+        <help>Collect NetFlow data on this firewall, this will automatically append localhost as NetFlow target. Please keep disabled when using a RAM disk (for size and consistency reasons).</help>
     </field>
     <field>
         <id>netflow.capture.version</id>