Fix lint errors and warnings

The CI gods demand it

```
warning: value assigned to `used_space` is never read
```

Don't know how to fix the other one in `generate_preview_count()`,
despite rust's attempt to help:

```
warning: value assigned to `available_space` is never read
   --> src/lineprinter.rs:868:9
    |
868 |         available_space -= len;
    |         ^^^^^^^^^^^^^^^
    |
    = help: maybe it is overwritten before being read?
```

src/lineprinter.rs

@@ -686,12 +686,17 @@ impl<'a, 'b, 'c> LinePrinter<'a, 'b, 'c> {
             available_space -= 1;
         }
 
-        let mut used_space = 0;
+        let mut used_space;
 
         if self.preview == Preview::Full {
             let quoted_object_keys = self.mode == Mode::Line;
             used_space =
-                self.generate_container_preview(flatjson, row, available_space, quoted_object_keys)?;
+                self.generate_container_preview(
+                    flatjson,
+                    row,
+                    available_space,
+                    quoted_object_keys,
+                )?;
 
             if self.trailing_comma {
                 used_space += 1;
@@ -706,8 +711,7 @@ impl<'a, 'b, 'c> LinePrinter<'a, 'b, 'c> {
                     )?;
                 }
             }
-        }
-        else if self.preview == Preview::None {
+        } else if self.preview == Preview::None {
             self.highlight_str(
                 " ",
                 Some(self.value_range.end),
@@ -717,10 +721,8 @@ impl<'a, 'b, 'c> LinePrinter<'a, 'b, 'c> {
                 ),
             )?;
             used_space = 1;
-        }
-        else {
-            used_space =
-                self.generate_container_count(flatjson, row, available_space)?;
+        } else {
+            used_space = self.generate_container_count(flatjson, row, available_space)?;
         }
 
         Ok(used_space)
@@ -826,7 +828,7 @@ impl<'a, 'b, 'c> LinePrinter<'a, 'b, 'c> {
         &mut self,
         flatjson: &FlatJson,
         row: &Row,
-        mut available_space: isize
+        available_space: isize,
     ) -> Result<isize, fmt::Error> {
         debug_assert!(row.is_opening_of_container());
 
@@ -836,7 +838,7 @@ impl<'a, 'b, 'c> LinePrinter<'a, 'b, 'c> {
         }
 
         let mut next_sibling = row.first_child();
-        let mut count:usize = 0;
+        let mut count: usize = 0;
         while let OptionIndex::Index(child) = next_sibling {
             next_sibling = flatjson[child].next_sibling;
             count += 1;
@@ -846,14 +848,14 @@ impl<'a, 'b, 'c> LinePrinter<'a, 'b, 'c> {
         let mut count_str = format!(
             "{} {} item{} {}",
             container_type.open_str(),
-            count.to_string(),
+            count,
             if count == 1 { "" } else { "s" },
             container_type.close_str()
         );
 
         if count_str.len() as isize > available_space {
             count_str = format!(
-                 "{}…{}",
+                "{}…{}",
                 container_type.open_str(),
                 container_type.close_str()
             );
@@ -862,10 +864,9 @@ impl<'a, 'b, 'c> LinePrinter<'a, 'b, 'c> {
         self.highlight_str(
             &count_str,
             Some(self.value_range.start),
-            highlighting::PREVIEW_STYLES
+            highlighting::PREVIEW_STYLES,
         )?;
         let len = count_str.chars().count() as isize;
-        available_space -= len;
         Ok(len)
     }
 
@@ -1596,15 +1597,10 @@ mod tests {
             ..default_line_printer(&mut term)
         };
 
-        for (available_space, used_space, expected) in vec![
-            (14, 11, r#"[ 3 items ]"#),
-            (4,  3, r#"[…]"#),
-            (2,  0, r#""#),
-        ]
-        .into_iter()
+        for (available_space, used_space, expected) in
+            vec![(14, 11, r#"[ 3 items ]"#), (4,  3, r#"[…]"#), (2,  0, r#""#)].into_iter()
         {
-            let used =
-                line.generate_container_count(&fj_arr, &fj_arr[0], available_space)?;
+            let used = line.generate_container_count(&fj_arr, &fj_arr[0], available_space)?;
             assert_eq!(
                 expected,
                 line.terminal.output(),
@@ -1617,15 +1613,10 @@ mod tests {
             line.terminal.clear_output();
         }
 
-        for (available_space, used_space, expected) in vec![
-            (14, 11, r#"{ 2 items }"#),
-            (4,  3, r#"{…}"#),
-            (2,  0, r#""#),
-        ]
-        .into_iter()
+        for (available_space, used_space, expected) in
+            vec![(14, 11, r#"{ 2 items }"#), (4,  3, r#"{…}"#), (2,  0, r#""#)].into_iter()
         {
-            let used =
-                line.generate_container_count(&fj_obj, &fj_obj[0], available_space)?;
+            let used = line.generate_container_count(&fj_obj, &fj_obj[0], available_space)?;
             assert_eq!(
                 expected,
                 line.terminal.output(),
@@ -1638,13 +1629,9 @@ mod tests {
             line.terminal.clear_output();
         }
 
-        for (available_space, used_space, expected) in vec![
-            (14, 10, r#"{ 1 item }"#),
-        ]
-        .into_iter()
+        for (available_space, used_space, expected) in vec![(14, 10, r#"{ 1 item }"#)].into_iter()
         {
-            let used =
-                line.generate_container_count(&fj_one, &fj_one[0], available_space)?;
+            let used = line.generate_container_count(&fj_one, &fj_one[0], available_space)?;
             assert_eq!(
                 expected,
                 line.terminal.output(),

src/viewer.rs

@@ -732,8 +732,7 @@ impl JsonViewer {
         if val == Preview::None && self.mode == Mode::Line {
             // Emit a warning....?
             self.preview = Preview::Count;
-        }
-        else {
+        } else {
             self.preview = val;
         }
     }
@@ -749,8 +748,7 @@ impl JsonViewer {
                 Preview::Count => Preview::None,
                 Preview::None => Preview::Full,
             }
-        }
-        else {
+        } else {
             self.preview = match self.preview {
                 Preview::Full => Preview::Count,
                 Preview::Count => Preview::Full,