Update nightscout-setup.md

Provided information for users who use mmol instead of mgdl on how to set BG targets in Heroku so don't end up with "urgent high" alerts when they are in range.

Author: JazzyCar

docs/docs/While You Wait For Gear/nightscout-setup.md

@@ -83,19 +83,19 @@ your data, customized watchfaces with your OpenAPS data, and integration with IF
 </tr>
 <tr>
 <th>BG_HIGH</th>
-<td>Enter the numeric value of BG you’d like as an urgent high alarm.</td>
+<td>Enter the numeric value of BG you’d like as an urgent high alarm. (Note: For users outside the US, this needs to be set in mgdl. Take your desired mmol number and multiply it by 18).  </td>
 </tr>
 <tr>
 <th>BG_TARGET_TOP</th>
-<td>Enter the numeric value of the top of your target BG.</td>
+<td>Enter the numeric value of the top of your target BG.(Note: For users outside the US, this needs to be set in mgdl. Take your desired mmol number and multiply it by 18).</td>
 </tr>
 <tr>
 <th>BG_TARGET_BOTTOM</th>
-<td>Enter the numeric value of the bottom of your target BG.</td>
+<td>Enter the numeric value of the bottom of your target BG.(Note: For users outside the US, this needs to be set in mgdl. Take your desired mmol number and multiply it by 18).</td>
 </tr>
 <tr>
 <th>BG_LOW</th>
-<td>Enter the numeric value of the BG you’d like as an urgent low alarm.</td>
+<td>Enter the numeric value of the BG you’d like as an urgent low alarm.(Note: For users outside the US, this needs to be set in mgdl. Take your desired mmol number and multiply it by 18).</td>
 </tr>
 <tr>
 <th>PUSHOVER lines</th>