fn add_custom_completions(
acc: &mut Completions,
ctx: &CompletionContext<'_>,
cap: SnippetCap,
scope: SnippetScope,
) -> Option<()>fn add_custom_completions(
acc: &mut Completions,
ctx: &CompletionContext<'_>,
cap: SnippetCap,
scope: SnippetScope,
) -> Option<()>