i18n: make Danish available in UI (#7287)

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### Tests

- I added test coverage for Go changes...
  - [ ] in their respective `*_test.go` for unit tests.
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- I added test coverage for JavaScript changes...
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- I tested via manual method for the changes
  - [X] in terminal using the "make" command.

### Documentation

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### Release notes

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<!--start release-notes-assistant-->

## Release notes
<!--URL:https://codeberg.org/forgejo/forgejo-->
- Localization
  - [PR](https://codeberg.org/forgejo/forgejo/pulls/7287): <!--number 7287 --><!--line 0 --><!--description aTE4bjogbWFrZSBEYW5pc2ggYXZhaWxhYmxlIGluIFVJ-->i18n: make Danish available in UI<!--description-->
<!--end release-notes-assistant-->

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7287
Reviewed-by: 0ko <0ko@noreply.codeberg.org>
Co-authored-by: Tacaly <frederick@tacaly.com>
Co-committed-by: Tacaly <frederick@tacaly.com>

custom/conf/app.example.ini

@@ -2407,8 +2407,8 @@ LEVEL = Info
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; The first locale will be used as the default if user browser's language doesn't match any locale in the list.
-;LANGS = en-US,zh-CN,zh-HK,zh-TW,de-DE,nds,fr-FR,nl-NL,lv-LV,ru-RU,uk-UA,ja-JP,es-ES,pt-BR,pt-PT,pl-PL,bg,it-IT,fi-FI,fil,eo,tr-TR,cs-CZ,sl,sv-SE,ko-KR,el-GR,fa-IR,hu-HU,id-ID
-;NAMES = English,简体中文,繁體中文（香港）,繁體中文（台灣）,Deutsch,Plattdüütsch,Français,Nederlands,Latviešu,Русский,Українська,日本語,Español,Português do Brasil,Português de Portugal,Polski,Български,Italiano,Suomi,Filipino,Esperanto,Türkçe,Čeština,Slovenščina,Svenska,한국어,Ελληνικά,فارسی,Magyar nyelv,Bahasa Indonesia
+;LANGS = en-US,zh-CN,zh-HK,zh-TW,da,de-DE,nds,fr-FR,nl-NL,lv-LV,ru-RU,uk-UA,ja-JP,es-ES,pt-BR,pt-PT,pl-PL,bg,it-IT,fi-FI,fil,eo,tr-TR,cs-CZ,sl,sv-SE,ko-KR,el-GR,fa-IR,hu-HU,id-ID
+;NAMES = English,简体中文,繁體中文（香港）,繁體中文（台灣）,Danish,Deutsch,Plattdüütsch,Français,Nederlands,Latviešu,Русский,Українська,日本語,Español,Português do Brasil,Português de Portugal,Polski,Български,Italiano,Suomi,Filipino,Esperanto,Türkçe,Čeština,Slovenščina,Svenska,한국어,Ελληνικά,فارسی,Magyar nyelv,Bahasa Indonesia
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

modules/setting/i18n.go

@@ -9,6 +9,7 @@ var defaultI18nLangNames = []string{
 	"zh-CN", "简体中文",
 	"zh-HK", "繁體中文（香港）",
 	"zh-TW", "繁體中文（台灣）",
+	"da", "Danish",
 	"de-DE", "Deutsch",
 	"nds", "Plattdüütsch",
 	"fr-FR", "Français",