public RuleContext addChild(RuleContext ruleInvocation) {
		return addAnyChild(ruleInvocation);
	}
Add a parse tree node to this as a child.  Works for
 internal and leaf nodes. Does not set parent link;
 other add methods must do that. Other addChild methods
 call this.

 We cannot set the parent pointer of the incoming node
 because the existing interfaces do not have a setParent()
 method and I don't want to break backward compatibility for this.

 @since 4.7
runtime/Java/src/org/antlr/v4/runtime/ParserRuleContext.java