Mayor Anthony A. Williams acknowledged yesterday that the outcome of the school board ballot issue has highlighted the District's racial divide and put him at odds once more with the city's African American community. "This thing does sort out along those lines," Williams (D) said yesterday. "And it makes it all the more important . . . for us to be as inclusive as possible, and to put candidates forward who enjoy wide support and represent the same kind of inclusiveness." In an interview, the mayor said he plans to address the racial divide. "In the next day or two, we're going to bring both ...