fix(cli): remove hard coded comment char with linting COMMIT_EDIT_MSG

When running the cli and passing the `--edit` flag the comment char
was hard coded to a `#`. Even if there is a `commentChar` set in the
`parserOpts` the cli will override it with a `#`.

Now the cli will only set it to a `#` if its not already set in the
`parserOpts`

Fixes Issue: conventional-changelog#2351

Author: AdeAttwood

@commitlint/cli/fixtures/comment-char/commitlint.config.js

@@ -0,0 +1,10 @@
+module.exports = {
+	rules: {
+		'subject-empty': [2, 'never']
+	},
+	parserPreset: {
+        parserOpts: {
+            commentChar: '$'
+        }
+    },
+};

@commitlint/cli/src/cli.test.ts

@@ -329,6 +329,16 @@ test('should handle --amend with signoff', async () => {
 	expect(commit).toBeTruthy();
 }, 10000);
 
+test('should fail with an empty message and a commentChar is set', async () => {
+	const cwd = await gitBootstrap('fixtures/comment-char');
+	await execa('git', ['config', '--local', 'core.commentChar', '$'], {cwd});
+	await fs.writeFile(path.join(cwd, '.git', 'COMMIT_EDITMSG'), '#1234');
+
+	const actual = await cli(['--edit', '.git/COMMIT_EDITMSG'], {cwd})();
+	expect(actual.stdout).toContain('[subject-empty]');
+	expect(actual.exitCode).toBe(1);
+});
+
 test('should handle linting with issue prefixes', async () => {
 	const cwd = await gitBootstrap('fixtures/issue-prefixes');
 	const actual = await cli([], {cwd})('foobar REF-1');

@commitlint/cli/src/cli.ts

@@ -205,8 +205,10 @@ async function main(options: CliFlags) {
 	}
 	const format = loadFormatter(loaded, flags);
 
-	// Strip comments if reading from `.git/COMMIT_EDIT_MSG`
-	if (flags.edit) {
+	// Strip comments if reading from `.git/COMMIT_EDIT_MSG` using the
+	// commentChar from the parser preset falling back to a `#` if that is not
+	// set
+	if (flags.edit && typeof opts.parserOpts.commentChar !== 'string') {
 		opts.parserOpts.commentChar = '#';
 	}