chore: remove unmaintained atty crate (flxzt#1178)

* Remove unmaintained crate "atty"

* Fix lint

Cargo.toml

@@ -24,7 +24,6 @@ adw = { version = "0.6.0", package = "libadwaita", features = ["v1_5"] }
 anyhow = "1.0"
 approx = "0.5.1"
 async-fs = "2.1"
-atty = "0.2.14"
 base64 = "0.22.1"
 cairo-rs = { version = "0.19.4", features = ["v1_18", "png", "svg", "pdf"] }
 chrono = "0.4.38"

crates/rnote-cli/Cargo.toml

@@ -13,7 +13,6 @@ rnote-compose = { workspace = true, features = ["clap-derive"] }
 rnote-engine = { workspace = true, features = ["cli"] }
 
 anyhow = { workspace = true }
-atty = { workspace = true }
 clap = { workspace = true }
 dialoguer = { workspace = true }
 indicatif = { workspace = true }

crates/rnote-cli/src/export.rs

@@ -10,6 +10,7 @@ use rnote_engine::engine::export::{
 };
 use rnote_engine::engine::EngineSnapshot;
 use rnote_engine::{Engine, SelectionCollision};
+use std::io::{self, IsTerminal};
 use std::path::{Path, PathBuf};
 
 #[allow(clippy::too_many_arguments)]
@@ -427,7 +428,7 @@ pub(crate) fn file_conflict_prompt_action(
     if !output_file.exists() {
         return Ok(None);
     }
-    if atty::isnt(atty::Stream::Stdout) {
+    if !io::stdout().is_terminal() {
         return Err(anyhow::anyhow!(
             "File conflict for file \"{}\" detected and terminal is not interactive. Option \"--on-conflict\" needs to be supplied.", output_file.display()
         ));