Update Frontend Development Workflow type's comment to be clearer

An implementor expressed confusion, thinking that the comment applied to the
value displayed in the setting as opposed to the setting itself.

This commit makes the meaning of the comment clearer - in that, rather than
the setting not being available, it has no effect.

Author: navarr

app/code/Magento/Developer/etc/adminhtml/system.xml

@@ -11,7 +11,7 @@
                 <label>Frontend Development Workflow</label>
                 <field id="type" translate="label comment" type="select" sortOrder="1" showInDefault="1" canRestore="1">
                     <label>Workflow type</label>
-                    <comment>Not available in production mode.</comment>
+                    <comment>Modifying this configuration has no effect in production mode.</comment>
                     <source_model>Magento\Developer\Model\Config\Source\WorkflowType</source_model>
                     <frontend_model>Magento\Developer\Block\Adminhtml\System\Config\WorkflowType</frontend_model>
                     <backend_model>Magento\Developer\Model\Config\Backend\WorkflowType</backend_model>

app/code/Magento/Developer/i18n/en_US.csv

@@ -9,4 +9,4 @@
 "Allowed IPs (comma separated)","Allowed IPs (comma separated)"
 "Leave empty for access from any location.","Leave empty for access from any location."
 "Log to File","Log to File"
-"Not available in production mode.","Not available in production mode."
+"Modifying this configuration has no effect in production mode.","Modifying this configuration has no effect in production mode."