Update left-over reference to Core.GlobalMethods (#59976)

Renaming happened in f9b7d27 / PR
#59158 by @JeffBezanson

Author: fingolfin

doc/src/devdocs/functions.md

@@ -7,7 +7,7 @@ This document will explain how functions, method definitions, and method tables
 
 Every function in Julia is a generic function. A generic function is conceptually a single function,
 but consists of many definitions, or methods. The methods of a generic function are stored in a
-method table. There is one global method table (type `MethodTable`) named `Core.GlobalMethods`. Any
+method table. There is one global method table (type `MethodTable`) named `Core.methodtable`. Any
 default operation on methods (such as calls) uses that table.
 
 ## [Function calls](@id Function-calls)