Fix newline handling for tex-fmt input and output.

src/lint/latex-formatter/tex-fmt.ts

@@ -42,14 +42,15 @@ async function formatDocument(document: vscode.TextDocument, range?: vscode.Rang
             resolve(vscode.TextEdit.replace(range ?? document.validateRange(new vscode.Range(0, 0, Number.MAX_VALUE, Number.MAX_VALUE)), stdoutStr))
         })
     })
-
-    // write the document to the process, and add a newline at the end
-    process.stdin?.write(document.getText(range)+'\n')
-    process.stdin?.end()
-    const edits = await promise
-    // remove extra newline at the end
+
+    // 2024-12-4, for tex-fmt 0.4.7, when using `--stdin`, it requires a newline at the end of the input; Therefore, we need to add a newline at the end of the input if it doesn't exist, and remove it from the output if it exists.
+    const text = document.getText(range);
+    const endsWithNewline = text.endsWith('\n');
+    process.stdin?.write(endsWithNewline ? text : text + '\n');
+    process.stdin?.end();
+    const edits = await promise;
     if (edits) {
-        edits.newText = edits.newText.replace(/\n$/, '')
+        edits.newText = endsWithNewline ? edits.newText : edits.newText.replace(/\n$/, '');
     }
     return edits
 }