checks for anchor with consequent whitespaces fail in 3.12.2

[lmolkova]

Passes in 3.11.2 and fails in 3.12.2:

1. Whitespaces separated by special characters (no workaround)

   [migrating from <= v1.18.0](#migrating-from--v1180)
   
   ### Migrating from `<= v1.18.0`
   

   Changing to #migrating-from-v1180 passes markdown-lint-check, but it breaks navigation in VSCode and other link checkers (e.g. table of content).

2. Consequent whitespaces typo (easy to workaround)

   [Client/server examples using `network.peer.*`](#clientserver-examples-using--networkpeer)
   
   ##### Client/server examples using  `network.peer.*`
   

Could be related to similar issues: #348, #337

[chris-grabcad]

We use megalinter to run markdown-link-check on our PRs and our markdown files have TOCs generated via the markdown all in one vscode extension.

Having updated megalinter recently this bug has started to cause a lot of unnecessary noise about broken links that are not broken - with no sensible way of silencing them