chore: remove coverage file auto generator

Author: comphead

dev/release/rat_exclude_files.txt

@@ -12,7 +12,6 @@ dev/diffs/iceberg/*.diff
 dev/release/requirements.txt
 dev/release/rat_exclude_files.txt
 docs/comet-*
-docs/spark_builtin_expr_coverage.txt
 docs/source/_static/images/*.svg
 docs/source/_static/images/comet-dataflow.excalidraw
 docs/source/contributor-guide/benchmark-results/**/*.json