update

Update indices of attributes in @list for a change in the text they refer to.

The change that this function applies is removing @remove bytes at position @pos and inserting @add bytes instead.

Attributes that fall entirely in the (@pos, @pos + @remove) range are removed.

Attributes that start or end inside the (@pos, @pos + @remove) range are shortened to reflect the removal.

Attributes start and end positions are updated if they are behind @pos + @remove.

Parameters