Merge pull request #494 from arduino/lunnea/mega-datasheet-updates

Operating temp

Author: lunnea

content/hardware/02.hero/boards/mega-2560/datasheet/datasheet.md

@@ -74,7 +74,7 @@ Arduino® Mega 2560 is a successor board of Arduino Mega,  it is dedicated to ap
 ### Recommended Operating Conditions
 | Symbol | Description                                       | Min        | Max     |
 | ------ | ------------------------------------------------- | ---------- | ------- | 
-|        |  Conservative thermal limits for the whole board: |  -40 °C    | 85 °C   |
+|   TOP  |  Operating temperature:                           |  -40 °C    | 85 °C   |