sqlup-maybe-capitalize-symbol modified to ignore symbols prefixed by "."

[nverno]

I'm not sure if there are cases when sql keywords should be upcased when prefixed by a ".", but I find it annoying when my column names are upcased, eg. "t.name" => "t.NAME". This just modifies sqlup-maybe-capitalize-symbol to ignore symbols prefixed by ".", in case your interested. (also trivially adds lexical binding).