Tidy up help command text (#2566)

crates/nu-cli/src/commands/benchmark.rs

@@ -30,7 +30,7 @@ impl WholeStreamCommand for Benchmark {
     }
 
     fn usage(&self) -> &str {
-        "Runs a block and return the time it took to do execute it. Eg) benchmark { echo $nu.env.NAME }"
+        "Runs a block and returns the time it took to execute it"
     }
 
     async fn run(
@@ -40,6 +40,14 @@ impl WholeStreamCommand for Benchmark {
     ) -> Result<OutputStream, ShellError> {
         benchmark(args, registry).await
     }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Benchmarks a command within a block",
+            example: "benchmark { sleep 500ms }",
+            result: None,
+        }]
+    }
 }
 
 async fn benchmark(

crates/nu-cli/src/commands/clear.rs

@@ -17,7 +17,7 @@ impl WholeStreamCommand for Clear {
     }
 
     fn usage(&self) -> &str {
-        "clears the terminal"
+        "Clears the terminal"
     }
 
     async fn run(&self, _: CommandArgs, _: &CommandRegistry) -> Result<OutputStream, ShellError> {

crates/nu-cli/src/commands/date/command.rs

@@ -16,7 +16,7 @@ impl WholeStreamCommand for Command {
     }
 
     fn usage(&self) -> &str {
-        "Work with dates."
+        "Apply date function"
     }
 
     async fn run(

crates/nu-cli/src/commands/group_by.rs

@@ -28,7 +28,7 @@ impl WholeStreamCommand for GroupBy {
     }
 
     fn usage(&self) -> &str {
-        "create a new table grouped."
+        "Create a new table grouped."
     }
 
     async fn run(

crates/nu-cli/src/commands/move_/command.rs

@@ -17,7 +17,7 @@ impl WholeStreamCommand for Command {
     }
 
     fn usage(&self) -> &str {
-        "moves across desired subcommand."
+        "Moves across desired subcommand."
     }
 
     async fn run(

crates/nu-cli/src/commands/run_external.rs

@@ -48,7 +48,15 @@ impl WholeStreamCommand for RunExternalCommand {
     }
 
     fn usage(&self) -> &str {
-        ""
+        "Runs external command (not a nushell builtin)"
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Run the external echo command",
+            example: "run_external echo 'nushell'",
+            result: None,
+        }]
     }
 
     async fn run(

crates/nu-cli/src/commands/sleep.rs

@@ -37,7 +37,7 @@ impl WholeStreamCommand for Sleep {
     }
 
     fn usage(&self) -> &str {
-        "delay for a specified amount of time"
+        "Delay for a specified amount of time"
     }
 
     async fn run(