`pbts` generating syntax error on types when using multi-line `@typedef`s in static code

[LavissaWoW]

protobuf.js version: 7.3.0

Using @typedef definitions on static code generates invalid type syntax.
Any property after the first declared property will be prefixed with let

/**
 * @typedef {Object} MyType
 * @property {string} prop1
 * @property {number} prop2
 * @property {number] prop3
 */

When running pbts, this will be converted to:

type MyType = {
  prop1: string;
  let prop2: number;
  let prop3: number;
}

This isn't valid type syntax.

The problem occurs here:

protobuf.js/cli/lib/tsd-jsdoc/publish.js

Lines 394 to 396 in 0a0cdb6

	else if (element.properties && element.properties.length)
	element.properties.forEach(writeProperty);
	--indent;

forEach passes (value, index), and writePropertys second argument declare will then be populated with index.

protobuf.js/cli/lib/tsd-jsdoc/publish.js

Lines 400 to 404 in 0a0cdb6

	function writeProperty(property, declare) {
	writeComment(property.description);
	if (declare)
	write("let ");
	write(property.name);

Thus, the declare condition will be true for every element past array index 0.

[LavissaWoW]

I'm happy to whip up a short PR to address the issue