Revert "Upgrade to Rust 1.83 (#9511)" (#9617)

This reverts commit cf20673197 (#9511) due
to failure on powerpc64le in https://github.com/astral-sh/uv/pull/9612

crates/uv-scripts/src/lib.rs

@@ -350,7 +350,7 @@ impl ScriptTag {
         let mut lines = contents.lines();
 
         // Ensure that the first line is exactly `# /// script`.
-        if lines.next().is_none_or(|line| line != "# /// script") {
+        if !lines.next().is_some_and(|line| line == "# /// script") {
             return Ok(None);
         }