Update Navigator.md

Explain the purpose of the json files

Navigator Pages/Navigator.md

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 # Navigator Pages
 
 This folder provides the function of storing json files which can be used to pre-generate framework pages in the [DISARM Navigator](https://disarmfoundation.github.io/disarm-navigator/)
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+The following is a list of json files contained in this folder, with descriptions:
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+- **1.6update.json:** All new techniques and sub-techniques introduced in the 1.6 framework update
+- **fullframework.json:** All framework content with IDs (used to skip the "Create new layer" stage)