Module inline 

Inline token types and specifications

This module defines the token types for inline parsing. Inline elements are span-based
elements that can start and end at arbitrary positions within text content. Unlike the
line-based tokens (core and line), inline tokens operate at the character level and can
be nested within each other.

For the complete inline grammar specification, see specs/v1/grammar-inline.lex.

Related token modules:
- [core](super::core) - Character and word-level tokens from the logos lexer
- [line](super::line) - Line-based tokens for the main parser

Inline Token Types

These are the inline element types supported by lex:

    - Strong: *text* (bold/emphasis)
    - Emphasis: _text_ (italic)
    - Code: `text` (monospace, literal)
    - Math: #formula# (mathematical notation, literal)
    - Reference: [target] (links, citations, footnotes)

References support multiple subtypes including:
    - Citations: [@key] or [@key1; @key2, pp. 42-45]
    - Footnotes: [^label] or [42]
    - Session references: [#2.1]
    - URLs: [https://example.com]
    - File paths: [./path/to/file]
    - TK placeholders: [TK] or [TK-identifier]
    - General references: [Section Title]

Inline elements have these properties:
- Clear start and end markers (single character tokens)
- Can be nested (except literal types)
- Cannot break parent element boundaries
- No space allowed between marker and content

Token Specifications

Each inline type is defined by an InlineSpec that specifies:
- The kind of inline element (from InlineKind enum)
- Start and end tokens (characters)
- Whether it's literal (no nested parsing inside)
- Optional post-processing callback for complex logic

Citation Parsing

Citations are a specialized form of reference that follow academic citation format.
The reference token [target] is post-processed to detect citations starting with @.
Citation parsing is handled by [crate::lex::inlines::citations] which extracts:
- Multiple citation keys (separated by ; or ,)
- Optional page locators (p. or pp. followed by page ranges)
- Page ranges in various formats: single pages, ranges, or lists

Enums

InlineKind

The type of inline element