refactor/printf ~ fix cargo clippy complaint (clippy::needless_borrow)

src/uu/printf/src/tokenize/num_format/formatters/cninetyninehexfloatf.rs

@@ -26,7 +26,7 @@ impl Formatter for CninetyNineHexFloatf {
     ) -> Option<FormatPrimitive> {
         let second_field = field.second_field.unwrap_or(6) + 1;
         let analysis = FloatAnalysis::analyze(
-            &str_in,
+            str_in,
             initial_prefix,
             Some(second_field as usize),
             None,

src/uu/printf/src/tokenize/num_format/formatters/float_common.rs

@@ -298,11 +298,11 @@ pub fn get_primitive_dec(
 pub fn primitive_to_str_common(prim: &FormatPrimitive, field: &FormatField) -> String {
     let mut final_str = String::new();
     if let Some(ref prefix) = prim.prefix {
-        final_str.push_str(&prefix);
+        final_str.push_str(prefix);
     }
     match prim.pre_decimal {
         Some(ref pre_decimal) => {
-            final_str.push_str(&pre_decimal);
+            final_str.push_str(pre_decimal);
         }
         None => {
             panic!(

src/uu/printf/src/tokenize/num_format/formatters/floatf.rs

@@ -21,7 +21,7 @@ impl Formatter for Floatf {
     ) -> Option<FormatPrimitive> {
         let second_field = field.second_field.unwrap_or(6) + 1;
         let analysis = FloatAnalysis::analyze(
-            &str_in,
+            str_in,
             initial_prefix,
             None,
             Some(second_field as usize),

src/uu/printf/src/tokenize/num_format/formatters/intf.rs

@@ -252,7 +252,7 @@ impl Formatter for Intf {
     fn primitive_to_str(&self, prim: &FormatPrimitive, field: FormatField) -> String {
         let mut final_str: String = String::new();
         if let Some(ref prefix) = prim.prefix {
-            final_str.push_str(&prefix);
+            final_str.push_str(prefix);
         }
         // integral second fields is zero-padded minimum-width
         // which gets handled before general minimum-width
@@ -266,7 +266,7 @@ impl Formatter for Intf {
                         i -= 1;
                     }
                 }
-                final_str.push_str(&pre_decimal);
+                final_str.push_str(pre_decimal);
             }
             None => {
                 panic!(

src/uu/printf/src/tokenize/num_format/num_format.rs

@@ -235,7 +235,7 @@ pub fn num_format(field: &FormatField, in_str_opt: Option<&String>) -> Option<St
                     let as_str = format!("{}", provided_num);
                     let initial_prefix = get_initial_prefix(
                         &as_str,
-                        &field.field_type
+                        field.field_type
                     );
                     tmp=formatter.get_primitive(field, &initial_prefix, &as_str)
                         .expect("err during default provided num");

src/uu/printf/src/tokenize/sub.rs

@@ -275,7 +275,7 @@ impl SubParser {
                 }
                 None => {
                     text_so_far.push('%');
-                    err_conv(&text_so_far);
+                    err_conv(text_so_far);
                     false
                 }
             }