docs: Annotate more places with required features

examples/tutorial_builder/01_quick.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command, Command};
 use std::path::Path;
 

examples/tutorial_builder/02_app_settings.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command, AppSettings};
 
 fn main() {

examples/tutorial_builder/02_crate.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 
 fn main() {

examples/tutorial_builder/03_01_flag_bool.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 
 fn main() {

examples/tutorial_builder/03_01_flag_count.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 
 fn main() {

examples/tutorial_builder/03_02_option.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 
 fn main() {

examples/tutorial_builder/03_03_positional.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 
 fn main() {

examples/tutorial_builder/03_04_subcommands.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command, Command};
 
 fn main() {

examples/tutorial_builder/03_05_default_values.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 
 fn main() {

examples/tutorial_builder/04_01_enum.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command, ArgEnum, PossibleValue};
 
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ArgEnum)]

examples/tutorial_builder/04_01_possible.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 
 fn main() {

examples/tutorial_builder/04_02_parse.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 
 fn main() {

examples/tutorial_builder/04_02_validate.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 use std::ops::RangeInclusive;
 use std::str::FromStr;

examples/tutorial_builder/04_03_relations.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command, ArgGroup};
 
 fn main() {

examples/tutorial_builder/04_04_custom.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command, ErrorKind};
 
 fn main() {

examples/tutorial_builder/05_01_assert.rs

@@ -1,3 +1,5 @@
+// Note: this requires the `cargo` feature
+
 use clap::{arg, command};
 
 fn main() {