Changed "pair" to "triplet" in Vector3 definition

(cherry picked from commit ce1fcfcff9d5056127deb8da70f8823be1654e1f)

doc/classes/Vector3.xml

@@ -4,7 +4,7 @@
 		Vector used for 3D math.
 	</brief_description>
 	<description>
-		3-element structure that can be used to represent positions in 3D space or any other pair of numeric values.
+		3-element structure that can be used to represent positions in 3D space or any other triplet of numeric values.
 		[b]Note:[/b] In a boolean context, a Vector3 will evaluate to [code]false[/code] if it's equal to [code]Vector3(0, 0, 0)[/code]. Otherwise, a Vector3 will always evaluate to [code]true[/code].
 	</description>
 	<tutorials>