udpate rust toolchain to rust 1.81.0 (#14473)

# Description

With the release of rust 1.83.0 it's time to update to rust 1.81.0.

Cargo.toml

@@ -10,7 +10,7 @@ homepage = "https://www.nushell.sh"
 license = "MIT"
 name = "nu"
 repository = "https://github.com/nushell/nushell"
-rust-version = "1.80.1"
+rust-version = "1.81.0"
 version = "0.100.1"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

crates/nu-cli/src/util.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::byte_char_slices)]
+
 use nu_cmd_base::hook::eval_hook;
 use nu_engine::{eval_block, eval_block_with_early_return};
 use nu_parser::{lex, parse, unescape_unquote_string, Token, TokenContents};

crates/nu-parser/src/parse_patterns.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::byte_char_slices)]
+
 use crate::{
     lex, lite_parse,
     parser::{is_variable, parse_value},
@@ -7,7 +9,6 @@ use nu_protocol::{
     engine::StateWorkingSet,
     ParseError, Span, SyntaxShape, Type, VarId,
 };
-
 pub fn garbage(span: Span) -> MatchPattern {
     MatchPattern {
         pattern: Pattern::Garbage,

crates/nu-parser/src/parse_shape_specs.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::byte_char_slices)]
+
 use crate::{lex::lex_signature, parser::parse_value, trim_quotes, TokenContents};
 use nu_protocol::{engine::StateWorkingSet, ParseError, Span, SyntaxShape, Type};
 

crates/nu-parser/src/parser.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::byte_char_slices)]
+
 use crate::{
     lex::{is_assignment_operator, lex, lex_n_tokens, lex_signature, LexState},
     lite_parser::{lite_parse, LiteCommand, LitePipeline, LiteRedirection, LiteRedirectionTarget},

crates/nu-parser/tests/test_lex.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::byte_char_slices)]
+
 use nu_parser::{lex, lex_n_tokens, lex_signature, LexState, Token, TokenContents};
 use nu_protocol::{ParseError, Span};
 

rust-toolchain.toml

@@ -16,4 +16,4 @@ profile = "default"
 # use in nushell, we may opt to use the bleeding edge stable version of rust.
 # I believe rust is on a 6 week release cycle and nushell is on a 4 week release cycle.
 # So, every two nushell releases, this version number should be bumped by one.
-channel = "1.80.1"
+channel = "1.81.0"