all: use fixdocs tool to store package documentation in doc.go

Add copyright header to doc.go

Keep original comment style (e.g. line comments and block comments).

internal/math32/math.go

@@ -6,8 +6,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package math32 provides float32 versions of standard library math package
-// routines used by gonum/blas/native.
 package math32 // import "gonum.org/v1/gonum/internal/math32"
 
 import (