Modify gitignore

Add comments to 'sections'.
Ignore *.bak files and rejected patch files.
Ignore rangers history and bookmarks file.

.gitignore

@@ -1,10 +1,23 @@
+# Ignore backup files
 *.bkp
+*.bak
+
+# Ignore all gitignores in this repo but this one
 .gitignore
 !/.gitignore
 
+# Ignore files generated by rejected patches etc.
+*.rej
+*.orig
+
 /.config/git/github.config
 /.config/git/gitlab.config
 /.config/git/user.config
+
 /.config/vim/.netrwhist
+
 /.config/zsh/.zcompdump
 /.config/zsh/plugins/completion/_msg
+
+/.config/ranger/bookmarks
+/.config/ranger/history