Headline shortcut in ID with underline when headline starts with a number

[sanjaay]

Bug Report

Steps to reproduce

1. Create a headline in your docsify project
   example ## 1. my headline
2. check the parameter of the id

The URL is: URL?id=_1-my-headline
Should be: URL?id=1-my-headline

What is current behaviour

The id is: URL?_id=_1-my-headline

What is the expected behaviour

The id should be : URL?id=1-my-headline

There should be no underline before at the beginning.

[Koooooo-7]

Thx for ur report.
It is the way how we solve the siderbar links rn.
According to the W3C docs id-selectors.

An ID selector consists of a “number sign” (U+0023, #) immediately followed by the ID value, which must be a CSS identifier.

When a head starts with digit, it is not a valid selector , so we add the _ to make it works as anchor on sidebar.