unicode: various documentation tweaks

The comment on IsOneOf regarding Latin-1 was an implementation detail:
when the function is called internally, that condition is true. It used to matter,
but now the comment is a dreg. The function works fine if the character is
Latin-1, so we just delete the comment.

Fixes #2966.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5655047

src/pkg/unicode/graphic.go

@@ -53,7 +53,6 @@ func IsPrint(r rune) bool {
 }
 
 // IsOneOf reports whether the rune is a member of one of the ranges.
-// The rune is known to be above Latin-1.
 func IsOneOf(set []*RangeTable, r rune) bool {
 	for _, inside := range set {
 		if Is(inside, r) {
@@ -65,7 +64,7 @@ func IsOneOf(set []*RangeTable, r rune) bool {
 
 // IsControl reports whether the rune is a control character.
 // The C (Other) Unicode category includes more code points
-// such as surrogates; use Is(C, rune) to test for them.
+// such as surrogates; use Is(C, r) to test for them.
 func IsControl(r rune) bool {
 	if uint32(r) <= MaxLatin1 {
 		return properties[uint8(r)]&pC != 0

src/pkg/unicode/letter.go

@@ -60,8 +60,8 @@ type CaseRange struct {
 // Methods of SpecialCase customize (by overriding) the standard mappings.
 type SpecialCase []CaseRange
 
-//BUG(r): Provide a mechanism for full case folding (those that involve
-// multiple runes in the input or output).
+// BUG(r): There is no mechanism for full case folding, that is, for
+// characters that involve multiple runes in the input or output.
 
 // Indices into the Delta arrays inside CaseRanges for case mapping.
 const (
@@ -288,7 +288,7 @@ type foldPair struct {
 // SimpleFold iterates over Unicode code points equivalent under
 // the Unicode-defined simple case folding.  Among the code points
 // equivalent to rune (including rune itself), SimpleFold returns the
-// smallest r >= rune if one exists, or else the smallest r >= 0. 
+// smallest rune >= r if one exists, or else the smallest rune >= 0. 
 //
 // For example:
 //	SimpleFold('A') = 'a'

src/pkg/unicode/maketables.go

@@ -417,7 +417,7 @@ func printCategories() {
 	fmt.Printf("const Version = %q\n\n", version())
 
 	if *tablelist == "all" {
-		fmt.Println("// Categories is the set of Unicode data tables.")
+		fmt.Println("// Categories is the set of Unicode category tables.")
 		fmt.Println("var Categories = map[string] *RangeTable {")
 		for _, k := range allCategories() {
 			fmt.Printf("\t%q: %s,\n", k, k)

src/pkg/unicode/tables.go

@@ -7,7 +7,7 @@ package unicode
 // Version is the Unicode edition from which the tables are derived.
 const Version = "6.0.0"
 
-// Categories is the set of Unicode data tables.
+// Categories is the set of Unicode category tables.
 var Categories = map[string]*RangeTable{
 	"C":  C,
 	"Cc": Cc,