Remove wrong "(default)"
Remove wrong "(default)"

`blank_lines_upper_bound` has default value `1`, not `2`.

graydon/rust,aidancully/rust,aidancully/rust,rust-lang/rustfmt,graydon/rust,rust-lang/rustfmt,graydon/rust,SingingTree/rustfmt,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,SingingTree/rustfmt,graydon/rust