eslint-plugin-tsdoc: allow policies to be ignored in tsdoc/syntax rule

Now that less-strict parsing for @param tags is merged (https://github.com/microsoft/tsdoc/issues/128), I'd love to be able to loosen the requirements of the tsdoc/syntax rule to allow for certain deviations from the expected syntax.

Primarily, VSCode's built-in JSDoc support automatically adds a doc comment where each @param tag is followed immediately by a description, without the expected hyphen. With the following .eslintrc configuration:

{
  rules: {
    'tsdoc/syntax': 'warn'
  }
}

This snippet is valid:

/**
 * Description
 * @param a - first number
 * @param b - second number
 */
const add = (a: number, b: number) => a + b;

While this snippet:

/**
 * Description
 * @param a first number
 * @param b second number
 */
const add = (a: number, b: number) => a + b;

Warns with the following:

tsdoc-param-tag-missing-hyphen: The @param block should be followed by a parameter name and then a hyphen eslint(tsdoc/syntax)

I'd love to be able to ignore this particular syntax deviation with something like:

{
  rules: {
    'tsdoc/syntax': ['warn', ignore: ['tsdoc-param-tag-missing-hyphen'] ]
  }
}

Start with the eslint-plugin-tsdoc tsdoc/syntax rule and the less-strict @param parsing context in issue #128; compare the two examples and determine how rule options are represented. Done means a configuration can ignore tsdoc-param-tag-missing-hyphen while other syntax diagnostics still warn, with coverage for both forms.