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

This reverts commit b0a98102dc.

internal/math32/math.go

@@ -6,6 +6,8 @@
 // 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 (