license: update copyright notices to include contributors

Updates all copyright notices to include "Ghostty contributors" to
reflect the fact that Mitchell is not the sole copyright owner.

Also adds "Ghostty contributors" to the author section in the manpages,
linking https://github.com/ghostty-org/ghostty/graphs/contributors for
proper credit.

src/build/GhosttyI18n.zig

@@ -54,7 +54,7 @@ fn createUpdateStep(b: *std.Build) !*std.Build.Step {
         "--keyword=C_:1c,2",
         "--package-name=" ++ domain,
         "--msgid-bugs-address=m@mitchellh.com",
-        "--copyright-holder=Mitchell Hashimoto",
+        "--copyright-holder=\"Mitchell Hashimoto, Ghostty contributors\"",
         "-o",
         "-",
     });

src/build/mdgen/ghostty_1_footer.md

@@ -44,6 +44,7 @@ See GitHub issues: <https://github.com/ghostty-org/ghostty/issues>
 # AUTHOR
 
 Mitchell Hashimoto <m@mitchellh.com>
+Ghostty contributors <https://github.com/ghostty-org/ghostty/graphs/contributors>
 
 # SEE ALSO
 

src/build/mdgen/ghostty_5_footer.md

@@ -36,6 +36,7 @@ See GitHub issues: <https://github.com/ghostty-org/ghostty/issues>
 # AUTHOR
 
 Mitchell Hashimoto <m@mitchellh.com>
+Ghostty contributors <https://github.com/ghostty-org/ghostty/graphs/contributors>
 
 # SEE ALSO