Using a compatible rule with GitHub to slugify may be better. VS Code's intellisense looks like to be adopted compatible rule with GitHub in header slugs.
Generating slug for ID anchors must be able to disable because a generated slide snippets by Marp Core may be used in a middle of website. If conflicted IDs with exist web contents, an integrated web app may become broken.
Note
Marp CLI has not provided custom anchor link support in bespoke template. This implementation may motivate to support custom anchor links in bespoke template.
Providing built-in slugified headers in Marp Core will improve anchor navigation in Marp for VS Code.
Requirements
Using a compatible rule with GitHub to slugify may be better. VS Code's intellisense looks like to be adopted compatible rule with GitHub in header slugs.
Generating slug for ID anchors must be able to disable because a generated slide snippets by Marp Core may be used in a middle of website. If conflicted IDs with exist web contents, an integrated web app may become broken.
Note
Marp CLI has not provided custom anchor link support in bespoke template. This implementation may motivate to support custom anchor links in bespoke template.
Related