[RTL] Add pop_all, push_context and pop_context methods, and use it for print_rich to avoid unclosed tags.

doc/classes/RichTextLabel.xml

@@ -266,6 +266,18 @@
 				Terminates the current tag. Use after [code]push_*[/code] methods to close BBCodes manually. Does not need to follow [code]add_*[/code] methods.
 			</description>
 		</method>
+		<method name="pop_all">
+			<return type="void" />
+			<description>
+				Terminates all tags opened by [code]push_*[/code] methods.
+			</description>
+		</method>
+		<method name="pop_context">
+			<return type="void" />
+			<description>
+				Terminates tags opened after the last [method push_context] call (including context marker), or all tags if there's no context marker on the stack.
+			</description>
+		</method>
 		<method name="push_bgcolor">
 			<return type="void" />
 			<param index="0" name="bgcolor" type="Color" />
@@ -298,6 +310,12 @@
 				Adds a [code][color][/code] tag to the tag stack.
 			</description>
 		</method>
+		<method name="push_context">
+			<return type="void" />
+			<description>
+				Adds a context marker to the tag stack. See [method pop_context].
+			</description>
+		</method>
 		<method name="push_customfx">
 			<return type="void" />
 			<param index="0" name="effect" type="RichTextEffect" />