retro-extend.py: fix dictionary lookups

FossilOrigin-Name: a58bc1a4860fcf38c1931dbe3614ee9a88441279906d400d9c795c8093f8fbbb

RELEASE-NOTES

@@ -16,6 +16,7 @@
 
   - retro-describe(1) now uses embedded glossary data
   - retro-muri.py: increase memory size for initial image
+  - retro-extend.py: fix dictionary lookups
 
 - documentation
 

tools/retro-extend.py

@@ -353,7 +353,7 @@ class Retro:
         Dictionary = dict()
         header = self.memory[2]
         while header != 0:
-            named = self.extract_string(header + 4)
+            named = self.extract_string(header + 9)
             if not named in Dictionary:
                 Dictionary[named] = header
             header = self.memory[header]
@@ -366,7 +366,7 @@ class Retro:
         header = self.memory[2]
         Done = False
         while header != 0 and not Done:
-            if named == self.extract_string(header + 4):
+            if named == self.extract_string(header + 9):
                 self.Dictionary[named] = header
                 Done = True
             else: