adapt the documentation to reflect the new name

Author: Anaethelion

docs/modeling-guide.md

@@ -332,7 +332,7 @@ type FooOrBar = Foo | Bar
 
 An example of internal variants are the type mapping properties.
 
-#### External
+#### typed_keys_quirk
 
 The key that defines the variant is external to the definition, like in the
 case of aggregations in responses or suggesters.
@@ -343,15 +343,15 @@ name in the definition itself.
 The syntax is:
 
 ```ts
-/** @variants external */
+/** @variants typed_keys_quirk */
 
 /** @variant name='<field-name>' */
 ```
 
 For example:
 
 ```ts
-/** @variants external */
+/** @variants typed_keys_quirk */
 type FooAlias = Faz | Bar
 
 /** @variant name='faz' */
@@ -369,7 +369,7 @@ In the example above, `FooAlias` will look like this:
 
 ```json
 {
-  "faz": {
+  "name#faz": {
     "prop": "hello world"
   }
 }
@@ -379,7 +379,7 @@ or:
 
 ```json
 {
-  "bar": {
+  "name#bar": {
     "prop": true
   }
 }