Grammar "with the exception of"s are ambiguous

[epage]

I'm writing a grammar for rust-lang/rust#136889 and got the following result:

I took this to mean:

with the exception of:

• FRONTMATTER_FENCE
• CHAR

and thought I had a bug in my grammar and played around a bit before I realized the intention is:

CHAR
with the exception of:

• FRONTMATTER_FENCE

I feel like putting the exception warning below the grammar item would remove this ambiguity.