Remove references to two unknown lints in config

`option_map_unwrap_or` and `seek_rewind` are not current lints, and
cannot be referenced as having the `msrv` configuration option.

Author: samueltardieu

book/src/lint_configuration.md

@@ -873,15 +873,13 @@ The minimum rust version that the project supports. Defaults to the `rust-versio
 * [`needless_borrow`](https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow)
 * [`non_std_lazy_statics`](https://rust-lang.github.io/rust-clippy/master/index.html#non_std_lazy_statics)
 * [`option_as_ref_deref`](https://rust-lang.github.io/rust-clippy/master/index.html#option_as_ref_deref)
-* [`option_map_unwrap_or`](https://rust-lang.github.io/rust-clippy/master/index.html#option_map_unwrap_or)
 * [`ptr_as_ptr`](https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr)
 * [`question_mark`](https://rust-lang.github.io/rust-clippy/master/index.html#question_mark)
 * [`redundant_field_names`](https://rust-lang.github.io/rust-clippy/master/index.html#redundant_field_names)
 * [`redundant_static_lifetimes`](https://rust-lang.github.io/rust-clippy/master/index.html#redundant_static_lifetimes)
 * [`repeat_vec_with_capacity`](https://rust-lang.github.io/rust-clippy/master/index.html#repeat_vec_with_capacity)
 * [`same_item_push`](https://rust-lang.github.io/rust-clippy/master/index.html#same_item_push)
 * [`seek_from_current`](https://rust-lang.github.io/rust-clippy/master/index.html#seek_from_current)
-* [`seek_rewind`](https://rust-lang.github.io/rust-clippy/master/index.html#seek_rewind)
 * [`to_digit_is_some`](https://rust-lang.github.io/rust-clippy/master/index.html#to_digit_is_some)
 * [`transmute_ptr_to_ref`](https://rust-lang.github.io/rust-clippy/master/index.html#transmute_ptr_to_ref)
 * [`tuple_array_conversions`](https://rust-lang.github.io/rust-clippy/master/index.html#tuple_array_conversions)

clippy_config/src/conf.rs

@@ -775,15 +775,13 @@ define_Conf! {
         needless_borrow,
         non_std_lazy_statics,
         option_as_ref_deref,
-        option_map_unwrap_or,
         ptr_as_ptr,
         question_mark,
         redundant_field_names,
         redundant_static_lifetimes,
         repeat_vec_with_capacity,
         same_item_push,
         seek_from_current,
-        seek_rewind,
         to_digit_is_some,
         transmute_ptr_to_ref,
         tuple_array_conversions,