fix(clap_complete_nushell): Correctly handle commands whose short des…

…cription is more than one line

Found while trying to add Nushell completions to [`jj`](https://github.com/martinvonz/jj).

clap_complete_nushell/src/lib.rs

@@ -19,6 +19,7 @@
 #![warn(missing_docs, trivial_casts, unused_allocation, trivial_numeric_casts)]
 #![forbid(unsafe_code)]
 
+use clap::builder::StyledStr;
 use clap::{builder::PossibleValue, Arg, ArgAction, Command};
 use clap_complete::Generator;
 
@@ -75,7 +76,7 @@ fn append_value_completion_and_help(
             None => 0,
         };
 
-        s.push_str(format!("{:>width$}# {}", ' ', help).as_str());
+        s.push_str(format!("{:>width$}# {}", ' ', single_line_styled_str(help)).as_str());
     }
 
     s.push('\n');
@@ -180,6 +181,7 @@ fn generate_completion(completions: &mut String, cmd: &Command, is_subcommand: b
     }
 
     if let Some(about) = cmd.get_about() {
+        let about = single_line_styled_str(about);
         completions.push_str(format!("  # {about}\n").as_str());
     }
 
@@ -201,3 +203,7 @@ fn generate_completion(completions: &mut String, cmd: &Command, is_subcommand: b
         }
     }
 }
+
+fn single_line_styled_str(text: &StyledStr) -> String {
+    text.to_string().replace('\n', " ")
+}

clap_complete_nushell/tests/common.rs

@@ -18,7 +18,7 @@ pub fn basic_command(name: &'static str) -> Command {
         )
         .subcommand(
             Command::new("test")
-                .about("Subcommand")
+                .about("Subcommand\nwith a second line")
                 .arg(Arg::new("debug").short('d').action(ArgAction::Count)),
         )
 }
@@ -36,7 +36,7 @@ pub fn feature_sample_command(name: &'static str) -> Command {
         .arg(
             Arg::new("config")
                 .action(ArgAction::Count)
-                .help("some config file")
+                .help("some config file\nwith another line")
                 .short('c')
                 .visible_short_alias('C')
                 .long("config")

clap_complete_nushell/tests/snapshots/basic.nu

@@ -6,7 +6,7 @@ module completions {
     --help(-h)                # Print help
   ]
 
-  # Subcommand
+  # Subcommand with a second line
   export extern "my-app test" [
     -d
     -c
@@ -17,7 +17,7 @@ module completions {
   export extern "my-app help" [
   ]
 
-  # Subcommand
+  # Subcommand with a second line
   export extern "my-app help test" [
   ]
 

clap_complete_nushell/tests/snapshots/feature_sample.nu

@@ -7,9 +7,9 @@ module completions {
   # Tests completions
   export extern my-app [
     file?: string             # some input file
-    --config(-c)              # some config file
-    --conf                    # some config file
-    -C                        # some config file
+    --config(-c)              # some config file with another line
+    --conf                    # some config file with another line
+    -C                        # some config file with another line
     choice?: string@"nu-complete my-app choice"
     --help(-h)                # Print help
     --version(-V)             # Print version

clap_complete_nushell/tests/snapshots/special_commands.nu

@@ -7,9 +7,9 @@ module completions {
   # Tests completions
   export extern my-app [
     file?: string             # some input file
-    --config(-c)              # some config file
-    --conf                    # some config file
-    -C                        # some config file
+    --config(-c)              # some config file with another line
+    --conf                    # some config file with another line
+    -C                        # some config file with another line
     choice?: string@"nu-complete my-app choice"
     --help(-h)                # Print help
     --version(-V)             # Print version

clap_complete_nushell/tests/snapshots/sub_subcommands.nu

@@ -7,9 +7,9 @@ module completions {
   # Tests completions
   export extern my-app [
     file?: string             # some input file
-    --config(-c)              # some config file
-    --conf                    # some config file
-    -C                        # some config file
+    --config(-c)              # some config file with another line
+    --conf                    # some config file with another line
+    -C                        # some config file with another line
     choice?: string@"nu-complete my-app choice"
     --help(-h)                # Print help
     --version(-V)             # Print version