refactor(preprocess.py): use general variable name

Author: MaoSong2022

vrdu/preprocess.py

@@ -135,19 +135,19 @@ def replace_pdf_figures_with_png(original_tex: str) -> None:
 
     # Replace PDF paths with PNG paths
     for match in matches:
-        pdf_image_name = match[1]
-        pdf_image = os.path.join(
-            main_directory, os.path.join(graphic_path, pdf_image_name)
+        image_name = match[1]
+        image_file = os.path.join(
+            main_directory, os.path.join(graphic_path, image_name)
         )
-        if not os.path.exists(pdf_image):
-            raise FileNotFoundError(f"File not found: {pdf_image}")
+        if not os.path.exists(image_file):
+            raise FileNotFoundError(f"File not found: {image_file}")
 
-        png_image_name = os.path.splitext(pdf_image_name)[0] + ".png"
+        png_image_name = os.path.splitext(image_name)[0] + ".png"
         png_image = os.path.join(
             main_directory, os.path.join(graphic_path, png_image_name)
         )
 
-        utils.convert_pdf_figure_to_png_image(pdf_image, png_image)
+        utils.convert_pdf_figure_to_png_image(image_file, png_image)
 
         # replace the reference in tex file
         content = content.replace(match[1], png_image_name)