csharp: rename to match all other guides

We use xxxguide for filenames now, not xxx-style.

.github/CODEOWNERS

@@ -1,6 +1,6 @@
 # https://docs.github.com/en/github/creating-cloning-and-archiving-repositories/about-code-owners#codeowners-syntax
 
-csharp-style.md @jbcoe
+csharpguide.md @jbcoe
 htmlcssguide.html @tonyruscoe
 shellguide.md @eatnumber1 @vapier
 /go/ @chressie @gaal @katrinahoffert @kliegs @matttproud

404.html

@@ -13,6 +13,7 @@ window.onload = function() {
   const missingPage = location.pathname.substr(12);
   const map = {
     'cppguide.xml': 'cppguide.html',
+    'csharp-style.html': 'csharpguide.html',
     'eclipse-java-google-style.xml': 'https://github.com/google/google-java-format',
     'google-r-style.html': 'Rguide.html',
     'htmlcssguide.xml': 'htmlcssguide.html',

README.md

@@ -77,7 +77,7 @@ primarily optimizing for Google's internal needs.
 
 [angular]: https://angular.dev/style-guide
 [cpp]: https://google.github.io/styleguide/cppguide.html
-[csharp]: csharp-style.md
+[csharp]: csharpguide.md
 [swift]: https://google.github.io/swift/
 [objc]: objcguide.md
 [gh-tracker]: https://github.com/google/styleguide/issues