Fill in the blank in the Array, CenterContainer and Dictionary class reference (#4476)

(cherry picked from commit 4de3f8944e)

doc/base/classes.xml

@@ -4104,10 +4104,12 @@
 		</method>
 		<method name="pop_back">
 			<description>
+			Remove the last element of the array.
 			</description>
 		</method>
 		<method name="pop_front">
 			<description>
+			Remove the first element of the array.
 			</description>
 		</method>
 		<method name="push_back">
@@ -4121,6 +4123,7 @@
 			<argument index="0" name="value" type="var">
 			</argument>
 			<description>
+			Add an element at the beginning of the array.
 			</description>
 		</method>
 		<method name="remove">
@@ -7028,6 +7031,7 @@
 			<return type="bool">
 			</return>
 			<description>
+				Should put children to the top left corner instead of center of the container.
 			</description>
 		</method>
 	</methods>
@@ -9696,6 +9700,7 @@ This approximation makes straight segments between each point, then subdivides t
 			<argument index="0" name="json" type="String">
 			</argument>
 			<description>
+			Parse json text to the dictionary. Return OK when successed or the error code when failed.
 			</description>
 		</method>
 		<method name="size">
@@ -9709,6 +9714,7 @@ This approximation makes straight segments between each point, then subdivides t
 			<return type="String">
 			</return>
 			<description>
+			Return the dictionary as json text.
 			</description>
 		</method>
 	</methods>