fix(surround): allow multiple inline code spans in the same block

[AnthoHansen]

Problem

Since v1.5.2, applying inline code to a second non-contiguous selection within the same block silently does nothing. The surround method uses querySelector(this.tag) on the parent element to check if any <code> already exists in the block — if it does, the wrap() call is skipped entirely.

Root cause

// Before (broken)
const existingCodeTag = range.commonAncestorContainer.parentElement?.querySelector(this.tag);
if (!existingCodeTag) {
  this.wrap(range);
}

This 'existingCodeTag' guard introduced in 1.5.2 prevents applying inline code to a second non-contiguous selection when the block already contains a <code> element to prevent nested <code> elements, but the check is too broad, it fires even when the existing <code> is in a completely different part of the block. The check short-circuits via querySelector, silently doing nothing instead of wrapping the new selection.

Fix

Remove the block-level guard. The selection-level check (findParentTag) already handles the toggle correctly — if the cursor is inside an existing <code> it unwraps; otherwise it wraps. No additional check is needed.

// After (fixed)
if (termWrapper) {
  this.unwrap(termWrapper);
} else {
  this.wrap(range);
}

Testing

1. Create a paragraph block
2. Select a word → apply inline code ✅
3. Select a different word in the same block → apply inline code ✅ (was broken in 1.5.2)
4. Click inside an existing <code> span → apply inline code removes it ✅

Closes Issue #46