Add missing 'public' keywords to some Language methods

Add missing 'public' keywords to some Language methods

All of them are already being used outside the class:
* getFallbackLanguages
* getBookstoreList
* getFormattedNamespaces
* getNsText
* getFormattedNsText
* getGenderNsText
* needsGenderDistinction
* getNamespaceAliases
* getNamespaceIds
* getNsIndex
* getVariantname
* getDatePreferences
* getDefaultDateFormat
* getDatePreferenceMigrationMap
* getImageFiles
* getExtraUserToggles
* getMessageFromDB
* getMonthName
* getMonthNamesArray
* getMonthNameGen

Change-Id: Iff5495596c5a711259c45b4d57c453aad9526a9a