BOSTON - The federal government filed a lawsuit Friday alleging that the city's election division discriminates against Hispanic and Asian-American voters by not offering enough services for immigrants who do not speak English. Because of its growing Hispanic population, Boston has been required since 1992 to provide all election materials in Spanish, but the lawsuit alleges the city's elections Web site and notices posted in polling places were only in English. "Despite having had an unequivocal obligation — for 13 years — to provide Spanish language information to voters who need it...the city of Boston has consistently fallen well short...