Merge branch 'develop' into claude/json-view-docs-split-48c8e0

Port the json_view.md change of #6017 (reading a file into a string)
into json_view/differences.md, and point the links to json_view.md that
develop added in files.md, performance.md and parsing/index.md at
json_view/index.md.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/mkdocs.yml

@@ -130,6 +130,7 @@ nav:
           - features/element_access/unchecked_access.md
           - features/element_access/checked_access.md
           - features/element_access/default_value.md
+      - features/files.md
       - features/iterators.md
       - features/merge_patch.md
       - features/json_patch.md