Add missing space for build examples

[matias-santurio]

Fixes ziglang/www.ziglang.org#422

[jameschensmith]

@matias-santurio, I think the better option would to fix the spacing when appending the additional options (e.g., from "{s} " to " {s}"). There's a few of them in doctest.zig, so make sure to fix them all if you do this approach.

            for (code.additional_options) |option| {
                try build_args.append(option);
-               try shell_out.print("{s} ", .{option});
+               try shell_out.print(" {s}", .{option});
            }

[matias-santurio]

@matias-santurio, I think the better option would to fix the spacing when appending the additional options (e.g., from "{s} " to " {s}"). There's a few of them in doctest.zig, so make sure to fix them all if you do this approach.

            for (code.additional_options) |option| {
                try build_args.append(option);
-               try shell_out.print("{s} ", .{option});
+               try shell_out.print(" {s}", .{option});
            }

Yeah I like that better too, I just tried to do the minimal change possible tbh. If a maintainer prefers it, I can make that change.

[eliasdorneles]

Will this PR fix this problem in https://ziglang.org/learn/build-system/ ?

[eliasdorneles]

Looks like the same fix proposed already here: #1