Those documents are a pain for most people to read, though.
People need some redundancy and repetition. When they have some question, they want to find the answer in in one place, not piece it together by deduction from three distant sentences.
Also, write what? You wouldn't write a novel necessarily like documentation. In your novel's plot, if a character dies, you don't have to repeat that fact three times. Novels aren't intended to work that way. If they did, there would be an Index at the back, where you look for "death" under "d", and then there will be an "... of Jack Grape, 234" under that, and there you go: page 234 is where Jack Grape dies.
Or, conversely, people reading your programming language specification do not avoid reading the later sections first, for fear of spoiling the plot! "Wow, this declaration syntax is so exciting, it really has me on edge as to whether there is an object system ... but I'm afraid of reading ahead to spoil the surprise!"
Something written to be read from cover to cover in a linear way as a work of art requires a different approach from a reference work.