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

This reverts commit 963877e5f5.

lapack/lapack64/lapack64.go

@@ -2,6 +2,21 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// Package lapack64 provides a set of convenient wrapper functions for LAPACK
+// calls, as specified in the netlib standard (www.netlib.org).
+//
+// The native Go routines are used by default, and the Use function can be used
+// to set an alternative implementation.
+//
+// If the type of matrix (General, Symmetric, etc.) is known and fixed, it is
+// used in the wrapper signature. In many cases, however, the type of the matrix
+// changes during the call to the routine, for example the matrix is symmetric on
+// entry and is triangular on exit. In these cases the correct types should be checked
+// in the documentation.
+//
+// The full set of Lapack functions is very large, and it is not clear that a
+// full implementation is desirable, let alone feasible. Please open up an issue
+// if there is a specific function you need and/or are willing to implement.
 package lapack64 // import "gonum.org/v1/gonum/lapack/lapack64"
 
 import (