Error when linting a message with the word "fix" in it using custom parser preset

When using a custom parser preset, any form of the word "fix" seems to break parsing of references.

Running `echo "refs#111111 Fixed something" | commitlint` yields the following error:

```
{
references: [],
subject: 'Fixed something',
merge: null,
header: 'refs#111111 Fixed something',
body: null,
footer: null,
notes: [],
mentions: [],
revert: null,
raw: 'refs#111111 Fixed something\r\n'
}
⧗ input: refs#111111 Fixed something
✖ references may not be empty [references-empty]

✖ found 1 problems, 0 warnings
ⓘ Get help: https://github.com/conventional-changelog/commitlint/#what-is-commitlint
```

However, linting "refs#111111 This is a correct message" passes as expected.

`echo "refs#111111 This is a correct message" | commitlint`

```
{
references: [
{
action: null,
owner: null,
repository: null,
issue: '111111',
raw: 'refs#111111',
prefix: 'refs#'
}
],
subject: 'This is a correct message',
merge: null,
header: 'refs#111111 This is a correct message',
body: null,
footer: null,
notes: [],
mentions: [],
revert: null,
raw: 'refs#111111 This is a correct message\r\n'
}
```

## Expected Behavior

The mentioned commit message should pass validation

## Current Behavior

It seems as if any form of the word "fix" (e.g. "fixed", "fixes", "Fix..") must be the last word of the message or the linter will mistakenly fail.

## Affected packages

- [ ] cli
- [x] core (I suppose)
- [ ] prompt
- [ ] config-angular

## Steps to Reproduce (for bugs)

commitlint.config.js

module.exports = {

  parserPreset: './commitlint.preset',

  rules: {

    'debug': [2, 'always'],

    // Built-in rules

    'header-full-stop': [2, 'never'], // Cannot have a trailing dot character

    'references-empty': [2, 'never'], // Must have at least one referenced ticket

    'subject-empty': [2, 'never'], // Must have a message (not just refs)

    'subject-case': [2, 'always', 'sentence-case'], // Must be sentence-like (e.g. Added xy function)

    // Custom rules

    'subject-start': [2, 'never', ['-', 'refs', ':', '.']], // Message cannot start with these (format error)

    'references-format': [2, 'always', /^,? ?refs#\d{5,}/] // Ban invalid refs format

  },

  plugins: [

    {

      rules: {

        'debug': (parsed) => {

          console.log(parsed);

          return [true];

        },

        'subject-start': (parsed, when, value) => {

          const { subject } = parsed;

          if (!subject) {

            return [true]; // subject-empty should handle missing subject

          }

          const negated = when === 'never';

          const doesMach = negated ?

              value.some(v => subject.trim().startsWith(v)) :

              value.every(v => subject.trim().startsWith(v));

          return [

              negated ? !doesMach : doesMach,

              `Subject ${negated ? 'may not' : 'must'} start with "${value.join('", "')}"`

          ];

        },

        'references-format': (parsed, when, matcher) => {

          const { references } = parsed;

          const negated = when === 'never';

          const doesMach = negated ?

              references.some(ref => ref.raw.trim().match(matcher)) :

              references.every(ref => ref.raw.trim().match(matcher));

          return [

              negated ? !doesMach : doesMach,

              `References ${negated ? 'may not' : 'must'} match format "${matcher}"`

          ];

        }

      }

    }

  ]

};

commitlint.preset.js

module.exports = {

  parserOpts: {

    headerPattern: /^(?:(refs#\d{5,}(?:, ?refs#\d{5,})*) )?(.*)$/,

    //headerPattern: /^((?:refs#\d{5,},?)*) ?(.*)$/,

    headerCorrespondence: ['references', 'subject'],

    issuePrefixes: ['refs#'],

    issuePrefixesCaseSensitive: true

  },

};

## Context

I am trying to configure commitlint for our custom message format `refs#TICKETNO Sentence case message`, where ticketno is a number at least 6 digits wide.

## Your Environment

| Executable | Version |
| ---------------------: | :------ |
| `commitlint --version` | @commitlint/cli@17.0.2 |
| `git --version` | git version 2.35.3.windows.1 |
| `node --version` | v14.16.0 |