Change 'pattern matching' description to 'destructuring'

[maxgerber]

People have found the term 'pattern matching' confusing as they have usually heard it in the context of switch/case statements in JS, and would describe breaking out the tuple like this as destructuring (though both are actually accurate).

We could either change the description, or add something like this to the helpful resources section of the readme...
https://gist.github.com/yang-wei/4f563fbf81ff843e8b1e

elm-week/part1/syntax-workshop/Solutions.elm

Line 278 in 7a511fb

-- rewrite area using pattern matching