json: rename filename to match other guides

We strip off the "style" from the filename everywhere else,
so do that here too.

404.html

@@ -15,7 +15,8 @@ window.onload = function() {
     'cppguide.xml': 'cppguide.html',
     'google-r-style.html': 'Rguide.html',
     'htmlcssguide.xml': 'htmlcssguide.html',
-    'jsoncstyleguide.xml': 'jsoncstyleguide.html',
+    'jsoncstyleguide.html': 'jsoncguide.html',
+    'jsoncstyleguide.xml': 'jsoncguide.html',
     'objcguide.xml': 'objcguide.html',
     'Rguide.xml': 'Rguide.html',
     'shell.xml': 'shellguide.html',

README.md

@@ -82,7 +82,7 @@ primarily optimizing for Google's internal needs.
 [gh-tracker]: https://github.com/google/styleguide/issues
 [go]: go/
 [java]: https://google.github.io/styleguide/javaguide.html
-[json]: https://google.github.io/styleguide/jsoncstyleguide.html
+[json]: https://google.github.io/styleguide/jsoncguide.html
 [kotlin]: https://developer.android.com/kotlin/style-guide
 [py]: pyguide.md
 [r]: Rguide.md