feat(build): improve lint-locale-usage further (#8736)

Print out a list of all unused msgids
Handle Go files that make calls to translation.
Handle `models/unit/unit.go`, which stores msgids in `$Unit.NameKey`
Handle .locale.Tr in templates
Handle simple dynamically constructed `Tr("msgid-prefix." + SomeFunctionCall())`.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/8736
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: Ellen Εμιλία Άννα Zscheile <fogti+devel@ytrizja.de>
Co-committed-by: Ellen Εμιλία Άννα Zscheile <fogti+devel@ytrizja.de>

models/project/project.go

@@ -182,6 +182,8 @@ func init() {
 }
 
 // GetCardConfig retrieves the types of configurations project column cards could have
+//
+//llu:returnsTrKey
 func GetCardConfig() []CardConfig {
 	return []CardConfig{
 		{CardTypeTextOnly, "repo.projects.card_type.text_only"},