Clean up README, contribution guide, and repository metadata

- REUSE.toml: fix the Hedley path and SPDX id (CC0-1.0), mark the docset
  icons as the public-domain JSON logo
- CITATION.cff: v3.12.0 was released on 2025-04-11
- FILES.md: list all workflows, describe the Meson option defaults
- README: ctest -LE, table of contents, typos, stale Android/MinGW advice,
  moved links, merge duplicate Thanks entries, list the analysis tools
  used in CI
- CONTRIBUTING: iterative parser, json_literals.hpp is generated, links
- .gitignore: backups and release outputs; .gitattributes: mark
  generated files
- labeler: label other build systems and .github documentation
- MODULE.bazel: add the module version

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

.github/ISSUE_TEMPLATE/bug.yaml

@@ -52,7 +52,7 @@ body:
         If possible, provide a small and self-contained example that triggers
         the bug. Please understand that we cannot analyze and debug large code
         bases. Please do not paste screenshots here.
-      render: Shell
+      render: cpp
   - type: textarea
     id: output
     attributes:
@@ -79,7 +79,7 @@ body:
       description: >
         Which version of the library did you use? If it is a released version,
         please enter the version number (e.g., 3.12.0). Otherwise, please enter
-        the commit hash. If you got the library from another source as the
+        the commit hash. If you got the library from another source than the
         GitHub repository (e.g., via a package manager), please also state
         this.
     validations: