Add Finnish translation

CMake/Assets.cmake

@@ -5,7 +5,7 @@ if(NOT DEFINED DEVILUTIONX_ASSETS_OUTPUT_DIRECTORY)
   set(DEVILUTIONX_ASSETS_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/assets")
 endif()
 
-set(devilutionx_langs bg cs da de el es et fr hr hu it ja ko pl pt_BR ro ru uk sv tr zh_CN zh_TW)
+set(devilutionx_langs bg cs da de el es et fi fr hr hu it ja ko pl pt_BR ro ru uk sv tr zh_CN zh_TW)
 if(USE_GETTEXT_FROM_VCPKG)
   # vcpkg doesn't add its own tools directory to the search path
   list(APPEND Gettext_ROOT ${CMAKE_CURRENT_BINARY_DIR}/vcpkg_installed/${VCPKG_TARGET_TRIPLET}/tools/gettext/bin)

Source/options.cpp

@@ -1037,6 +1037,7 @@ void OptionEntryLanguageCode::CheckLanguagesAreInitialized() const
 	languages.emplace_back("pt_BR", "Português do Brasil");
 	languages.emplace_back("ro", "Română");
 	languages.emplace_back("ru", "Русский");
+	languages.emplace_back("fi", "Suomi");
 	languages.emplace_back("sv", "Svenska");
 	languages.emplace_back("tr", "Türkçe");
 	languages.emplace_back("uk", "Українська");

Source/utils/language.cpp

@@ -145,7 +145,7 @@ void SetPluralForm(std::string_view expression)
 		return;
 	}
 
-	// en, bg, da, de, es, it, sv
+	// en, bg, da, de, es, fi, it, sv
 	if (expression == "(n != 1)") {
 		GetLocalPluralId = PluralIfNotOne;
 		return;