docs: add docstrings

src/cli/validate_config.zig

@@ -20,7 +20,12 @@ pub const Options = struct {
     }
 };
 
-/// The `validate-config` command is used to validate a Ghostty config
+/// The `validate-config` command is used to validate a Ghostty config file.
+///
+/// When executed without any arguments, this will load the config from the default location.
+///
+/// The `--config-file` argument can be passed to validate a specific target config
+/// file in a non-default location.
 pub fn run(alloc: std.mem.Allocator) !u8 {
     var opts: Options = .{};
     defer opts.deinit();