fix: correct paths in gitignore file

.gitignore

 # quarto files/folders
 /.quarto/
 /_book/
-chapters_*/*.html
-chapters_*/*.pdf
-chapters_*/*.log
-chapters_*/slides_cache
-chapters_*/slides_files
+/_freeze/
+appendix/**/*.html
+appendix/**/*.pdf
+appendix/**/*.log
+appendix/**/slides_cache
+appendix/**/slides_files
+chapters/**/*.html
+chapters/**/*.pdf
+chapters/**/*.log
+chapters/**/slides_cache
+chapters/**/slides_files
 public/*
 
-# custom files/folders
-/Nextcloud/
-/toc/
-igfl_training_course_python_for_beginners.tsv