doc: Fix markup issues in classref

doc/classes/ClassDB.xml

@@ -67,7 +67,7 @@
 			</argument>
 			<description>
 				Returns an array with all the methods of [code]class[/code] or its ancestry if [code]no_inheritance[/code] is [code]false[/code]. Every element of the array is a [Dictionary] with the following keys: [code]args[/code], [code]default_args[/code], [code]flags[/code], [code]id[/code], [code]name[/code], [code]return: (class_name, hint, hint_string, name, type, usage)[/code].
-				[b]Note:[/code] In exported release builds the debug info is not available, so the returned dictionaries will contain only method names.
+				[b]Note:[/b] In exported release builds the debug info is not available, so the returned dictionaries will contain only method names.
 			</description>
 		</method>
 		<method name="class_get_property" qualifiers="const">

doc/classes/Control.xml

@@ -16,7 +16,7 @@
 	<tutorials>
 		<link title="GUI tutorial index">https://docs.godotengine.org/en/3.3/tutorials/gui/index.html</link>
 		<link title="Custom drawing in 2D">https://docs.godotengine.org/en/3.3/tutorials/2d/custom_drawing_in_2d.html</link>
-		<link title="Control node gallery">https://docs.godotengine.org/en/latest/tutorials/ui/control_node_gallery.html</link>
+		<link title="Control node gallery">https://docs.godotengine.org/en/3.3/tutorials/gui/control_node_gallery.html</link>
 		<link title="All GUI Demos">https://github.com/godotengine/godot-demo-projects/tree/master/gui</link>
 	</tutorials>
 	<methods>

modules/gdscript/doc_classes/@GDScript.xml

@@ -1112,7 +1112,7 @@
 				[codeblock]
 				sqrt(9) # Returns 3
 				[/codeblock]
-				[b]Note:[/b]Negative values of [code]s[/code] return NaN. If you need negative inputs, use [code]System.Numerics.Complex[/code] in C#.
+				[b]Note:[/b] Negative values of [code]s[/code] return NaN. If you need negative inputs, use [code]System.Numerics.Complex[/code] in C#.
 			</description>
 		</method>
 		<method name="step_decimals">