Various documentation improvements.

Sources/ComplexModule/Documentation.docc/Complex.md

@@ -1,12 +1,9 @@
 # ``Complex``
 
-A Complex number type that conforms to `AlgebraicField`
-(so all the normal arithmetic operations are available) and
-`ElementaryFunctions` (so all the usual math functions are
-available).
+A complex number type represented by its real and imaginary parts, and equipped
+with the usual arithmetic operators and math functions.
 
-A `Complex` value is represented with two `RealType` values, corresponding to
-the real and imaginary parts of the number.
+## Overview
 
 You can access these Cartesian components using the real and imaginary
 properties.

Sources/ComplexModule/Scale.swift

@@ -22,15 +22,15 @@
 // Complex! Obviously, that doesn't help anyone.
 
 extension Complex {
-  /// `self` multiplied by the real value `a`.
+  /// The result of multiplying this value by the real number `a`.
   ///
   /// Equivalent to `self * Complex(a)`, but may be computed more efficiently.
   @inlinable @inline(__always)
   public func multiplied(by a: RealType) -> Complex {
     Complex(x*a, y*a)
   }
 
-  /// `self` divided by the real value `a`.
+  /// The result of dividing this value by the real number `a`.
   ///
   /// More efficient than `self / Complex(a)`. May not produce exactly the
   /// same result, but will always be more accurate if they differ.