Add NRes format documentation and decompression algorithms

- Created `huffman_decompression.md` detailing the Huffman decompression algorithm used in NRes, including context structure, block modes, and decoding methods.
- Created `overview.md` for the NRes format, outlining file structure, header details, file entries, and packing algorithms.
- Updated `mkdocs.yml` to include new documentation files in the navigation structure.

mkdocs.yml

@@ -19,6 +19,16 @@ theme:
   palette:
     scheme: slate
 
+# Navigation
+nav:
+  - Home: index.md
+  - Specs:
+      - Assets:
+          - NRes:
+              - Документация по формату: specs/assets/nres/overview.md
+              - FRES Декомпрессия: specs/assets/nres/fres_decompression.md
+              - Huffman Декомпрессия: specs/assets/nres/huffman_decompression.md
+
 # Additional configuration
 extra:
   social: