fix: Build warnings

[brian6932]

Gets rid of these:

warning: unnecessary parentheses around closure body
  --> src\results.rs:87:54
   |
87 | ...                   .map(|(pos, ch)| (pos..pos + ch.len_utf8()))
   |                                        ^                        ^
   |
   = note: `#[warn(unused_parens)]` (part of `#[warn(unused)]`) on by default
help: remove these parentheses
   |
87 -                                     .map(|(pos, ch)| (pos..pos + ch.len_utf8()))
87 +                                     .map(|(pos, ch)| pos..pos + ch.len_utf8() )
   |

warning: hiding a lifetime that's elided elsewhere is confusing
   --> src\widget.rs:143:28
    |
143 | pub fn border_block(theme: &Theme, focused: bool) -> Block {
    |                            ^^^^^^                    ^^^^^ the same lifetime is hidden here
    |                            |
    |                            the lifetime is elided here
    |
    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
help: use `'_` for type paths
    |
143 | pub fn border_block(theme: &Theme, focused: bool) -> Block<'_> {
    |                                                           ++++

warning: `nyaa` (lib) generated 2 warnings (run `cargo fix --lib -p nyaa` to apply 2 suggestions)
warning: `nyaa` (bin "nyaa") generated 2 warnings (2 duplicates)