Modifications in response to review

Added duplicate_no_arg test

help/functions.md

@@ -106,6 +106,7 @@ Note that optional and variadic parameters are not typed.
 # Multiple dispatch
 [tagmultiple]: # (multiple)
 [tagdispatch]: # (dispatch)
+[tagmultipledispatch]: # (multipledispatch)
 
 Morpho supports *multiple dispatch*, whereby you can define several implementations of a function that accept different types:
 

test/types/multiple_dispatch/duplicate_no_arg.morpho

@@ -0,0 +1,12 @@
+// Duplicate implementations with no arguments. 
+
+fn f() {
+    return 0
+}
+
+fn f() {
+    return 1 
+}
+
+print f()
+// expect error 'MltplDisptchAmbg'

test/types/multiple_dispatch/duplicate_no_type.morpho

@@ -1,5 +1,4 @@
 // Duplicate implementations with one argument no Type annotations.
-// This one currently segfaults due to an infinite loop.
 
 fn f(x) {
     return 0

test/types/multiple_dispatch/namespace_for_new.morpho

@@ -9,6 +9,5 @@ fn f(Matrix a) {
 
 }
 
-// Do we want this to be a new implementation for the namespace function, or this is not intended / allowed?
 f(Matrix(2,2))
 // expect: [ 2, 2 ]