test/[n-r]*.go: add documentation

The rename ones needed redoing.

R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/5698054

test/rename.go

@@ -4,70 +4,95 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// Test that predeclared names can be redeclared by the user.
+
 package main
 
 import "fmt"
 
 func main() {
 	n :=
-		bool +
+		append +
+			bool +
 			byte +
-			float +
+			complex +
+			complex64 +
+			complex128 +
+			cap +
+			close +
+			delete +
+			error +
+			false +
 			float32 +
 			float64 +
+			imag +
 			int +
 			int8 +
 			int16 +
 			int32 +
 			int64 +
+			len +
+			make +
+			new +
+			nil +
+			panic +
+			print +
+			println +
+			real +
+			recover +
+			rune +
+			string +
+			true +
 			uint +
 			uint8 +
 			uint16 +
 			uint32 +
 			uint64 +
 			uintptr +
-			true +
-			false +
-			iota +
-			nil +
-			cap +
-			len +
-			make +
-			new +
-			panic +
-			print +
-			println
-	if n != 27*28/2 {
-		fmt.Println("BUG: wrong n", n, 27*28/2)
+			iota
+	if n != NUM*(NUM-1)/2 {
+		fmt.Println("BUG: wrong n", n, NUM*(NUM-1)/2)
 	}
 }
 
 const (
-	bool    = 1
-	byte    = 2
-	float   = 3
-	float32 = 4
-	float64 = 5
-	int     = 6
-	int8    = 7
-	int16   = 8
-	int32   = 9
-	int64   = 10
-	uint    = 11
-	uint8   = 12
-	uint16  = 13
-	uint32  = 14
-	uint64  = 15
-	uintptr = 16
-	true    = 17
-	false   = 18
-	iota    = 19
-	nil     = 20
-	cap     = 21
-	len     = 22
-	make    = 23
-	new     = 24
-	panic   = 25
-	print   = 26
-	println = 27
+	append = iota
+	bool
+	byte
+	complex
+	complex64
+	complex128
+	cap
+	close
+	delete
+	error
+	false
+	float32
+	float64
+	imag
+	int
+	int8
+	int16
+	int32
+	int64
+	len
+	make
+	new
+	nil
+	panic
+	print
+	println
+	real
+	recover
+	rune
+	string
+	true
+	uint
+	uint8
+	uint16
+	uint32
+	uint64
+	uintptr
+	NUM
+	iota = 0
 )