BibliographyMeta wrongly cased/documented

[Adomas Ven]

This is the typescript

type BibliographyMeta = {
    max_offset: number;
    entry_spacing: number;
    line_spacing: number;
    hanging_indent: boolean;
    /** the second-field-align value of the CSL style */
    secondFieldAlign: null  | "flush" | "margin";
    /** Format-specific metadata */
    formatMeta: any,
};

The actual properties are all camel cased instead of snake cased. The camel case is preferred, but the typescript should be correct.

[Cormac Relf]

Fixed the TS issue in #94 but leaving open because it needs some doc