Use locator.slice(range) over locator.contents()[range] (#7759)

**Summary** Refactoring inspired by
https://github.com/astral-sh/ruff/pull/7741#discussion_r1342168033

crates/ruff_linter/src/checkers/noqa.rs

@@ -230,7 +230,13 @@ fn delete_noqa(range: TextRange, locator: &Locator) -> Edit {
         Edit::deletion(range.start() - leading_space_len, line_range.end())
     }
     // Ex) `x = 1  # noqa  # type: ignore`
-    else if locator.contents()[usize::from(range.end() + trailing_space_len)..].starts_with('#') {
+    else if locator
+        .slice(TextRange::new(
+            range.end() + trailing_space_len,
+            line_range.end(),
+        ))
+        .starts_with('#')
+    {
         Edit::deletion(range.start(), range.end() + trailing_space_len)
     }
     // Ex) `x = 1  # noqa here`

crates/ruff_linter/src/rules/flake8_simplify/rules/ast_if.rs

@@ -661,7 +661,11 @@ pub(crate) fn use_ternary_operator(checker: &mut Checker, stmt: &Stmt) {
     // Don't flag if the resulting expression would exceed the maximum line length.
     let line_start = checker.locator().line_start(stmt.start());
     if LineWidthBuilder::new(checker.settings.tab_size)
-        .add_str(&checker.locator().contents()[TextRange::new(line_start, stmt.start())])
+        .add_str(
+            checker
+                .locator()
+                .slice(TextRange::new(line_start, stmt.start())),
+        )
         .add_str(&contents)
         > checker.settings.line_length
     {
@@ -965,7 +969,11 @@ pub(crate) fn use_dict_get_with_default(checker: &mut Checker, stmt_if: &ast::St
     // Don't flag if the resulting expression would exceed the maximum line length.
     let line_start = checker.locator().line_start(stmt_if.start());
     if LineWidthBuilder::new(checker.settings.tab_size)
-        .add_str(&checker.locator().contents()[TextRange::new(line_start, stmt_if.start())])
+        .add_str(
+            checker
+                .locator()
+                .slice(TextRange::new(line_start, stmt_if.start())),
+        )
         .add_str(&contents)
         > checker.settings.line_length
     {

crates/ruff_linter/src/rules/flake8_simplify/rules/reimplemented_builtin.rs

@@ -99,7 +99,11 @@ pub(crate) fn convert_for_loop_to_any_all(checker: &mut Checker, stmt: &Stmt) {
             // Don't flag if the resulting expression would exceed the maximum line length.
             let line_start = checker.locator().line_start(stmt.start());
             if LineWidthBuilder::new(checker.settings.tab_size)
-                .add_str(&checker.locator().contents()[TextRange::new(line_start, stmt.start())])
+                .add_str(
+                    checker
+                        .locator()
+                        .slice(TextRange::new(line_start, stmt.start())),
+                )
                 .add_str(&contents)
                 > checker.settings.line_length
             {
@@ -181,7 +185,11 @@ pub(crate) fn convert_for_loop_to_any_all(checker: &mut Checker, stmt: &Stmt) {
             // Don't flag if the resulting expression would exceed the maximum line length.
             let line_start = checker.locator().line_start(stmt.start());
             if LineWidthBuilder::new(checker.settings.tab_size)
-                .add_str(&checker.locator().contents()[TextRange::new(line_start, stmt.start())])
+                .add_str(
+                    checker
+                        .locator()
+                        .slice(TextRange::new(line_start, stmt.start())),
+                )
                 .add_str(&contents)
                 > checker.settings.line_length
             {

crates/ruff_linter/src/rules/pyupgrade/rules/outdated_version_block.rs

@@ -298,7 +298,9 @@ fn fix_always_false_branch(
                 ..
             }) => {
                 debug_assert!(
-                    &checker.locator().contents()[TextRange::at(range.start(), "elif".text_len())]
+                    checker
+                        .locator()
+                        .slice(TextRange::at(range.start(), "elif".text_len()))
                         == "elif"
                 );
                 let end_location = range.start() + ("elif".text_len() - "if".text_len());