Write a bunch of docs.

doc/site/method-calls.markdown

@@ -64,11 +64,14 @@ Wren has a few prefix operators:
 They are just method calls on the operand without any other arguments. An
 expression like `!possible` just means "call the `!` method on `possible`".
 
-These operators are infix (they have operands on either side):
+We have a few other operators to play with. The remaining ones are
+infix—they have operators on either side. In order of increasing
+precedence, they are:
 
     :::wren
     == !=
     < > <= >=
+    .. ...
     | &
     + -
     * / %
@@ -78,6 +81,10 @@ left operand is the receiver, and the right operand gets passed to it. So
 `a + b` is semantically interpreted as "invoke the `+` method on `a`, passing
 it `b`".
 
+Most of these are probably familiar already. The `..` and `...` operators are
+"range" operators. The number type implements those and returns a range object,
+which can in turn be iterated over using a [`for`](loops.html) loop.
+
 ## Subscript operators
 
 Most languages use square brackets (`[]`) for working with collection-like