Refactor tool to take input file as positional argument

Signed-off-by: Muhammad Mahad <mahadtxt@gmail.com>

run.sh

@@ -58,9 +58,9 @@ process_files() {
 
             # if we have `.stderr` file
             if [[ -f "$stderr_file" ]]; then
-                rusttest-to-dg --file "$file" --stderr "$stderr_file" > "$output_file"
+                rusttest-to-dg "$file" --stderr "$stderr_file" > "$output_file"
             else
-                rusttest-to-dg --file "$file" > "$output_file"
+                rusttest-to-dg "$file" > "$output_file"
             fi
             mv "$output_file" "$file"
         fi

src/cli.rs

@@ -15,8 +15,7 @@ use {
 pub struct Arguments {
     /// The rust source file to convert into `DejaGnu` format
     #[arg(
-        short = 'f',
-        long = "file",
+        // positional argument
         value_name = "FILE",
         help = "The rust source file to convert into DejaGnu format"
     )]