Split primary test cases across multiple files, address bogus @ts-ignore issues.

CONTRIBUTING.md

@@ -23,7 +23,7 @@ Try to break the new code now, or else it will get broken later.
 
 Run tests before sending a pull request via `npm test` in the [usual manner](https://docs.npmjs.com/misc/scripts).
 Tests should all pass on all platforms.
-The test runner is [tape](https://www.npmjs.com/package/tape) and test cases are located in `test/markdownlint-test.js`.
+The test runner is [tape](https://www.npmjs.com/package/tape) and test cases are located in `test/markdownlint-test*.js`.
 When running tests, `test/*.md` files are enumerated, linted, and fail if any violations are missing a corresponding `{MD###}` marker in the test file.
 For example, the line `### Heading {MD001}` is expected to trigger the rule `MD001`.
 For cases where the marker text can not be present on the same line, the syntax `{MD###:#}` can be used to include a line number.

package.json

@@ -13,8 +13,8 @@
   },
   "bugs": "https://github.com/DavidAnson/markdownlint/issues",
   "scripts": {
-    "test": "node test/markdownlint-test.js",
-    "test-cover": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 node test/markdownlint-test.js",
+    "test": "tape test/markdownlint-test.js test/markdownlint-test-custom-rules.js test/markdownlint-test-helpers.js test/markdownlint-test-result-object.js test/markdownlint-test-scenarios.js",
+    "test-cover": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 tape test/markdownlint-test.js test/markdownlint-test-custom-rules.js test/markdownlint-test-helpers.js test/markdownlint-test-result-object.js test/markdownlint-test-scenarios.js",
     "test-declaration": "cd example/typescript && tsc && node type-check.js",
     "test-extra": "node test/markdownlint-test-extra.js",
     "lint": "eslint --max-warnings 0 lib helpers test schema && eslint --env browser --global markdownit --global markdownlint --rule \"no-unused-vars: 0, no-extend-native: 0, max-statements: 0, no-console: 0, no-var: 0, unicorn/prefer-add-event-listener: 0, unicorn/prefer-query-selector: 0, unicorn/prefer-replace-all: 0\" demo && eslint --rule \"no-console: 0, no-invalid-this: 0, no-shadow: 0, object-property-newline: 0, node/no-missing-require: 0, node/no-extraneous-require: 0\" example",