(#60) add next and previous links to bytes

[skanjo]

Had an issue using the default 11ty getPreviousCollectionItem and getNextCollectionItem filters. When using these filters in a macro the page object is not available. It is possible to pass the page object however a bug in the code checks value of this.page.lang to find the current language to resolve a locale page and results in an error despite passing in the page. The workaround is to also pass langCode which bypasses the bug. 11ty code references are below.

• https://github.com/11ty/eleventy/blob/v2.0.1/src/defaultConfig.js#L37
• https://github.com/11ty/eleventy/blob/v2.0.1/src/Filters/GetLocaleCollectionItem.js#L23

Current solution passes page object from the template and then pass page and hardcoded langCode to the filter in the macro.

resolves #60