Fix mkdocs config issues and add robots.txt for SEO

- Fix CHANGLOG.md typo (rename to CHANGELOG.md)
- Add site_description for search engine discoverability
- Fix magiclink repo from squidfunk/mkdocs-material to hakancelikdev/defineif
- Update copyright year to 2026
- Add robots.txt with sitemap reference

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hakancelikdev

docs/CHANGLOG.md docs/CHANGELOG.mddocs/CHANGLOG.md renamed to docs/CHANGELOG.md

@@ -0,0 +1,4 @@
+User-agent: *
+Allow: /
+
+Sitemap: https://defineif.hakancelik.dev/sitemap.xml

docs/robots.txt

@@ -1,5 +1,5 @@
 site_name: defineif
-site_description:
+site_description: A decorator that defines a method if the given condition is True.
 site_url: https://defineif.hakancelik.dev
 
 markdown_extensions:
@@ -29,8 +29,8 @@ markdown_extensions:
   - pymdownx.keys
   - pymdownx.magiclink:
       repo_url_shorthand: true
-      user: squidfunk
-      repo: mkdocs-material
+      user: hakancelikdev
+      repo: defineif
   - pymdownx.mark
   - pymdownx.smartsymbols
   - pymdownx.superfences:
@@ -112,13 +112,13 @@ theme:
   icon:
     repo: fontawesome/brands/github
 
-copyright: Copyright © 2020 - 2020 Hakan Çelik
+copyright: Copyright © 2020 - 2026 Hakan Çelik
 repo_url: https://github.com/hakancelikdev/defineif
 repo_name: hakancelikdev/defineif
 edit_uri: https://github.com/hakancelikdev/defineif/tree/main/docs
 
 nav:
   - Home: index.md
   - Contributing: CONTRIBUTING.md
-  - Changelog: CHANGLOG.md
+  - Changelog: CHANGELOG.md
   - Authors: AUTHORS.md