Mention 32-bit integer limit in the PoolIntArray documentation

(cherry picked from commit cb3676726b01825c6ff94284e4240fa305b8fc7d)

doc/classes/PoolIntArray.xml

@@ -4,7 +4,9 @@
 		A pooled [Array] of integers ([int]).
 	</brief_description>
 	<description>
-		An [Array] specifically designed to hold integer values ([int]). Optimized for memory usage, does not fragment the memory. Note that this type is passed by value and not by reference.
+		An [Array] specifically designed to hold integer values ([int]). Optimized for memory usage, does not fragment the memory.
+		[b]Note:[/b] This type is passed by value and not by reference.
+		[b]Note:[/b] This type is limited to signed 32-bit integers, which means it can only take values in the interval [code][-2^31, 2^31 - 1][/code], i.e. [code][-2147483648, 2147483647][/code]. Exceeding those bounds will wrap around. In comparison, [int] uses signed 64-bit integers which can hold much larger values.
 	</description>
 	<tutorials>
 	</tutorials>

doc/classes/Vector2.xml

@@ -4,7 +4,7 @@
 		Vector used for 2D math.
 	</brief_description>
 	<description>
-		2-element structure that can be used to represent positions in 2d space or any other pair of numeric values.
+		2-element structure that can be used to represent positions in 2D space or any other pair of numeric values.
 	</description>
 	<tutorials>
 		<link>https://docs.godotengine.org/en/3.1/tutorials/math/index.html</link>