Support TypeScript triple-slash directives

TypeScript uses triple-slash directives [1] (single-line comments
containing a single XML tag) to define compiler directives.
The `@arcticicestudio/eslint-config-base` configures the ESLint core
rule `spaced-comment` [2] and already defines exceptions and comment
markers for special use cases, but did not support triple-slash
directives. When running `eslint --fix` these comments in `*.d.ts` files
got malformed (`///` → `// /`) which resulted in invalid TypeScript
syntax.

To support triple-slash directives, the `/` marker has been added to the
`line` field.

[1]: https://www.typescriptlang.org/docs/handbook/triple-slash-directives.html
[2]: https://eslint.org/docs/rules/spaced-comment

Co-authored-by: Sven Greb <development@svengreb.de>

GH-50

packages/@arcticicestudio/eslint-config-base/rules/style.js

@@ -701,7 +701,14 @@ module.exports = {
       {
         line: {
           exceptions: ["+-"],
-          markers: ["!"],
+          markers: [
+            "!",
+            /*
+             * Support for TypeScript triple-slash directives.
+             * See https://www.typescriptlang.org/docs/handbook/triple-slash-directives.html for more details.
+             */
+            "/",
+          ],
         },
         block: {
           exceptions: ["+-"],