be consistent

src/clap_app.rs

@@ -146,10 +146,10 @@ pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {
                 .long("highlight-line")
                 .overrides_with("highlight-line")
                 .takes_value(true)
-                .value_name("n")
+                .value_name("N")
                 .help("Highlight a line.")
                 .long_help(
-                    "Highlight the nth line. The background color is changed to create contrast.",
+                    "Highlight the Nth line. The background color is changed to create contrast.",
                 ),
         )
         .arg(

src/printer.rs

@@ -302,16 +302,10 @@ impl<'a> Printer for InteractivePrinter<'a> {
         }
 
         // Line highlighting
-        let background = match self.config.highlight_line {
-            Some(line) => {
-                if line_number == line {
-                    self.background_highlight
-                } else {
-                    None
-                }
-            }
-            _ => None,
-        };
+        let background = self.config.highlight_line
+            .filter(|line| *line == line_number)
+            .map(|_| self.background_highlight)
+            .unwrap();
 
         // Line contents.
         if self.config.output_wrap == OutputWrap::None {