I think part of your confusion may stem from the multiple ways in which partnership can be used. Under one definition, partnership may refer to the general idea of a cooperative relationship, or to one's status of being a business partner. Here, partnership is uncountable, and would not take the definite article.
Partnership is an important marketing avenue for small businesses.
Marriage, traditionally, lies at the nexus of procreation and partnership.
Under another, countable, definition, partnership refers to an example of partnership, whether formal or not, and can take a definite article.
The partnership between Kraft and Starbucks ended acrimoniously.
Like the other accountants, she was saving every penny, planning to buy into the partnership the next year.
But in your example, partnership refers to a type of legal structure— one of many, like the limited liability company or the voluntary cooperative. You can interpret the here as indicating a particular type of limited partnership.
The use of articles is highly idiosyncratic, but saying it is used to genericize "animal, plant, and inventions" is not very helpful. The sea is none of those things, and neither is the past, for example. Moreover, invention is an exceptionally broad term that can refer to any human creation, and while we can speak of the quickstep (as one type of dance) or the republic (as one type of government), we would not say the golf (as one type of game) or the polyethylene (as one type of synthetic material) in the same way.