code review 12214044: strings: add IndexByte, for consistency with bytes package

src/pkg/strings/strings.go

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // Package strings implements simple functions to manipulate strings.
 package strings
 
 import (
         "unicode"
         "unicode/utf8"
@@ skipping 144 matching lines @@
                 i++
                 if h == hashsep && s[i-n:i] == sep {
                         return i - n
                 }
         }
         return -1
 }
 
 // IndexByte returns the index of the first instance of c in s, or -1 if c is not present in s.
 func IndexByte(s string, c byte) int {
-        // special case worth making fast
         for i := 0; i < len(s); i++ {
                 if s[i] == c {
                         return i
                 }
         }
         return -1
 }
 
 // LastIndex returns the index of the last instance of sep in s, or -1 if sep is not present in s.
 func LastIndex(s, sep string) int {
@@ skipping 554 matching lines @@
                 }
                 if r == tr {
                         continue
                 }
                 return false
         }
 
         // One string is empty.  Are both?
         return s == t
 }