[helix] Add a keymapping to open GitHub in blame view

This is *finally* added in https://github.com/cli/cli/releases/tag/v2.88.0

Author: rouge8

.config/helix.symlink/config.toml

@@ -60,5 +60,6 @@ p = [":echo %sh{prek run --files %{buffer_name}}", ":reload"]
 B = ":echo %sh{git blame -L %{cursor_line},+1 %{buffer_name}}"
 
 [keys.normal.space.W]
+B = ":sh gh browse --blame %{buffer_name}:%{cursor_line}"
 L = ":sh gh browse %{buffer_name}:%{cursor_line}"
 W = ":sh gh browse %{buffer_name}"