Apply suggestions from code review

Co-authored-by: Caleb Cartwright <calebcartwright@users.noreply.github.com>

Author: ArjenL

src/config/mod.rs

@@ -571,7 +571,7 @@ license_template_path = ""
 format_strings = false
 format_macro_matchers = false
 format_macro_bodies = true
-hex_literal_case = "Ignore"
+hex_literal_case = "Preserve"
 empty_item_single_line = true
 struct_lit_single_line = true
 fn_single_line = false

src/config/options.rs

@@ -131,11 +131,11 @@ pub enum ImportGranularity {
 #[config_type]
 pub enum HexLiteralCase {
     /// Leave the literal as-is
-    Ignore,
-    /// Uppercase the literal
-    ToUpper,
-    /// Lowercase the literal
-    ToLower,
+    Preserve,
+    /// Ensure all literals use uppercase lettering
+    Upper,
+    /// Ensure all literals use lowercase lettering
+    Lower,
 }
 
 #[config_type]

src/expr.rs

@@ -1217,9 +1217,9 @@ fn rewrite_int_lit(context: &RewriteContext<'_>, lit: &ast::Lit) -> Option<Strin
 
     if symbol.starts_with("0x") {
         let hex_lit = match context.config.hex_literal_case() {
-            HexLiteralCase::Ignore => None,
-            HexLiteralCase::ToUpper => Some(symbol[2..].to_ascii_uppercase()),
-            HexLiteralCase::ToLower => Some(symbol[2..].to_ascii_lowercase()),
+            HexLiteralCase::Preserve => None,
+            HexLiteralCase::Upper => Some(symbol[2..].to_ascii_uppercase()),
+            HexLiteralCase::Lower => Some(symbol[2..].to_ascii_lowercase()),
         };
         if let Some(hex_lit) = hex_lit {
             return Some(format!(

tests/source/hex_literal_lower.rs

@@ -1,4 +1,4 @@
-// rustfmt-hex_literal_case: ToLower
+// rustfmt-hex_literal_case: Lower
 fn main() {
     let h1 = 0xCAFE_5EA7;
     let h2 = 0xCAFE_F00Du32;

tests/source/hex_literal_upper.rs

@@ -1,5 +1,5 @@
-// rustfmt-hex_literal_case: ToUpper
+// rustfmt-hex_literal_case: Upper
 fn main() {
-    let h1 = 0xCAFE_5EA7;
+    let h1 = 0xCaFE_5ea7;
     let h2 = 0xCAFE_F00Du32;
 }

tests/target/hex_literal_ignore.rs

@@ -1,4 +1,4 @@
-// rustfmt-hex_literal_case: Ignore
+// rustfmt-hex_literal_case: Preserve
 fn main() {
     let h1 = 0xcAfE_5Ea7;
     let h2 = 0xCaFe_F00du32;

tests/target/hex_literal_lower.rs

@@ -1,4 +1,4 @@
-// rustfmt-hex_literal_case: ToLower
+// rustfmt-hex_literal_case: Lower
 fn main() {
     let h1 = 0xcafe_5ea7;
     let h2 = 0xcafe_f00du32;

tests/target/hex_literal_upper.rs

@@ -1,4 +1,4 @@
-// rustfmt-hex_literal_case: ToUpper
+// rustfmt-hex_literal_case: Upper
 fn main() {
     let h1 = 0xCAFE_5EA7;
     let h2 = 0xCAFE_F00Du32;