Updated OVERVIEW.md to the new infos required when adding a new leaf node to the tree (#19981)

Co-authored-by: Idriss AITHAFID <Idriss.AITHAFID@um6p.ma>

packages/react-devtools/OVERVIEW.md

@@ -70,7 +70,7 @@ For example, adding a root fiber with an id of 1:
 
 #### Adding a leaf node
 
-Adding a leaf node takes a variable number of numbers since we need to decode the name (and potentially the key):
+Adding a leaf node to the tree requires sending 7 numbers:
 
 1. add operation constant (`1`)
 1. fiber id
@@ -88,7 +88,6 @@ For example, adding a function component `<Foo>` with an id 2:
   1,   // ElementTypeClass
   1,   // parent id
   0,   // owner id
-  3,   // encoded display name size
   1,   // id of "Foo" displayName in the string table
   0,   // id of null key in the string table (always zero for null)
 ]