chore: Update .gitignore (#61)

- Ignore backup files

- Ignore project files

- Ignore compiler build directory

- Ignore documentation build directory

- Ignore Dylan packages and registry directories

Fix #45

Author: fraya

.gitignore

@@ -1,3 +1,19 @@
-_build
+# backup files
+*~
+*.bak
+.DS_Store
+
+# project file
 *.hdp
-deft-package-local.json
+
+# documentation build directory
+documentation/build/
+
+# compiler build directory
+_build/
+
+# dylan tool package cache
+_packages/
+
+# package registry folder
+registry/