test: disable coverage for .jison files

Coverage for `.jison` files doesn't make sense, since most of the
created JS lines are auto-generated.

If jison ever adds a source-map feature, we can renable coverage for
jison.

jest.config.js

@@ -11,6 +11,10 @@ module.exports = {
       { 'token-stack': true },
     ],
   },
+  coveragePathIgnorePatterns: [
+    '/node_modules/',
+    '^.+\\.jison$', // might be able to fix in future if .jison adds source-map support
+  ],
   transformIgnorePatterns: ['/node_modules/(?!dagre-d3-renderer/lib|khroma).*\\.js'],
   testPathIgnorePatterns: ['/node_modules/', '.cache', './cypress'],
   moduleNameMapper: {