primaryClass alias for arXiv entries

[matchatealeaf]

According to the biblatex documentation, archivePrefix and primaryClass were added as aliases for eprinttype and eprintclass respectively for arXiv compatibility.
See: https://mirrors.ctan.org/macros/latex/contrib/biblatex/doc/biblatex.pdf#subsubsection.2.2.5

However, it seems that only archivePrefix was implemented in this crate for eprinttype, and primaryClass for eprintclass is missing.

biblatex/src/lib.rs

Lines 764 to 775 in 190576a

	alias_fields! {
	address: "address" | "location",
	location: "location" | "address",
	annotation: "annotation" | "annote",
	eprint_type: "eprinttype" | "archiveprefix",
	journal: "journal" | "journaltitle",
	journal_title: "journaltitle" | "journal",
	sort_key: "key" | "sortkey" => String,
	file: "file" | "pdf" => String,
	school: "school" | "institution",
	institution: "institution" | "school",
	}

biblatex/src/lib.rs

Line 830 in 190576a

eprint_class: "eprintclass",

Is there a reason for the exclusion of primaryClass for eprintclass, or is it simply missed?