[Clippy] Use .is_empty() instead of comparison with 0/empty string.

src/app.rs

@@ -234,7 +234,7 @@ impl App {
                             let search_term = self.screen_writer.get_command("/").unwrap();
 
                             // In vim, /<CR> is a longcut for repeating the previous search.
-                            if search_term == "" {
+                            if search_term.is_empty() {
                                 let count = self.parse_input_buffer_as_number();
                                 jumped_to_search_match = true;
                                 self.jump_to_next_search_match(count)
@@ -260,7 +260,7 @@ impl App {
                             let search_term = self.screen_writer.get_command("?").unwrap();
 
                             // In vim, /<CR> is a longcut for repeating the previous search.
-                            if search_term == "" {
+                            if search_term.is_empty() {
                                 let count = self.parse_input_buffer_as_number();
                                 jumped_to_search_match = true;
                                 self.jump_to_prev_search_match(count)

src/flatjson.rs

@@ -451,7 +451,7 @@ fn flatten_json(serde_value: SerdeValue, flat_json: &mut Vec<Row>, parents: &mut
             ..row
         }),
         SerdeValue::Array(vs) => {
-            if vs.len() == 0 {
+            if vs.is_empty() {
                 flat_json.push(Row {
                     value: Value::EmptyArray,
                     ..row
@@ -522,7 +522,7 @@ fn flatten_json(serde_value: SerdeValue, flat_json: &mut Vec<Row>, parents: &mut
             }
         }
         SerdeValue::Object(obj) => {
-            if obj.len() == 0 {
+            if obj.is_empty() {
                 flat_json.push(Row {
                     value: Value::EmptyObject,
                     ..row

src/search.rs

@@ -152,7 +152,7 @@ impl SearchState {
     }
 
     pub fn any_matches(&self) -> bool {
-        self.matches.len() > 0
+        !self.matches.is_empty()
     }
 
     pub fn no_matches_message(&self) -> String {

src/truncatedstrview.rs

@@ -144,7 +144,7 @@ impl TruncatedStrView {
     /// this function, when called on the string the TruncatedStrView is
     /// associated with, returns true.
     pub fn can_str_fit_at_all(s: &str, available_space: isize) -> bool {
-        available_space > 0 || (available_space == 0 && s.len() == 0)
+        available_space > 0 || (available_space == 0 && s.is_empty())
     }
 
     /// Create a truncated view of a string that shows the beginning of
@@ -664,7 +664,7 @@ impl<'a> RangeAdjuster<'a> {
                 // But we have room to showing something...
                 self.available_space > 1 &&
                     // And there's something to show.
-                    self.s.len() > 0;
+                    !self.s.is_empty();
 
         let mut used_space = self.used_space;
         if showing_replacement_character {