Add Coq artifacts to .gitignore
# These are backup files generated by rustfmt.
**/*.rs.bk
+### Coq ###
+# Coq build artifacts
+.Makefile.d
+*.aux
+*.glob
+*.vo
+*.vok
+*.vos
+
### CLion ###
# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm.
# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
