Refactor attach_orphan_specifiers function to reduce complexity

[coderabbitai]

Problem

The attach_orphan_specifiers function in src/fences.rs has a fairly complex peekable loop that makes the specifier-attachment state transitions difficult to follow and maintain.

Current Implementation Concerns

• Complex state management within a single function
• Peekable iterator logic mixed with business logic
• Multiple conditional branches that are hard to reason about
• State transitions for tracking whether we're inside a fenced block

Proposed Solution

Refactor the function to improve maintainability and clarity:

1. Extract helper functions:

   • is_orphan_specifier(line: &str) -> bool - Check if a line is a valid orphan specifier
   • is_opening_fence_without_specifier(line: &str) -> bool - Check if line is an opening fence without language specifier
   • attach_specifier_to_fence(fence_line: &str, specifier: &str) -> String - Combine specifier with fence line

2. Use a state machine approach:

   • Define clear states: LookingForSpecifier, FoundSpecifier, InsideFence
   • Make state transitions explicit and easier to test
   • Use one pass with peekable() to match "lang" + "```" pairs

3. Separate concerns:

   • Line classification logic
   • State management
   • Line transformation

Benefits

• Improved readability and maintainability
• Easier unit testing of individual components
• Clearer separation of concerns
• More explicit state transitions

Related

• PR: Add fences option #100
• Original comment: https://github.com/leynos/mdtablefix/pull/100#issuecomment-[comment-id]
• Requested by: @leynos