fix lang code handling
When I search an app and enter the app page, the URL is e.g. https://f-droid.org/packages/org.fdroid.fdroid/ and the language changes to ZH-HANT though the mainpage language is ZH-HANS. However if I enter an app from https://f-droid.org/zh_Hans/packages/18/index.html, the URL is https://f-droid.org/zh_Hans/packages/org.fdroid.fdroid/ and the language is ZH-HANS.
- The search result can be changed to a page in selected language.
- How does the websit select the luanguage of https://f-droid.org/ ? I get ZH-HANT but I use ZH-HANS.
- The search page from mainpage is e.g. https://search.f-droid.org/?q=F-Droid&lang=zh_Hans but when I search again from search page I get https://search.f-droid.org/?q=F-Droid and the logo URL is https://f-droid.org/en. I thought if I select a language, all the page I get should be in the selected language.