[Typo] Fix multiple wrong single and double quotation marks

eBook/04.5.md

@@ -162,7 +162,7 @@ func main() {
 ```go
 package main
 
-import “fmt”
+import "fmt"
 
 func main() {
 	var n int16 = 34
@@ -171,8 +171,8 @@ func main() {
 	//m = n
 	m = int32(n)
 
-	fmt.Printf(“32 bit int is: %d\n”, m)
-	fmt.Printf(“16 bit int is: %d\n”, n)
+	fmt.Printf("32 bit int is: %d\n", m)
+	fmt.Printf("16 bit int is: %d\n", n)
 }
 ```
 
@@ -198,7 +198,7 @@ func Uint8FromInt(n int) (uint8, error) {
 	if 0 <= n && n <= math.MaxUint8 { // conversion is safe
 		return uint8(n), nil
 	}
-	return 0, fmt.Errorf(“%d is out of the uint8 range”, n)
+	return 0, fmt.Errorf("%d is out of the uint8 range", n)
 }
 ```
 
@@ -213,7 +213,7 @@ func IntFromFloat64(x float64) int {
 		}
 		return int(whole)
 	}
-	panic(fmt.Sprintf(“%g is out of the int32 range”, x))
+	panic(fmt.Sprintf("%g is out of the int32 range", x))
 }
 ```
 
@@ -234,7 +234,7 @@ Go 拥有以下复数类型：
 
 ```go
 var c1 complex64 = 5 + 10i
-fmt.Printf(“The value is: %v”, c1)
+fmt.Printf("The value is: %v", c1)
 // 输出： 5 + 10i
 ```
 
@@ -447,14 +447,14 @@ func main() {
 
 ```go
 package main
-import “fmt”
+import "fmt"
 
 type TZ int
 
 func main() {
 	var a, b TZ = 3, 4
 	c := a + b
-	fmt.Printf(“c has the value: %d”, c) // 输出：c has the value: 7
+	fmt.Printf("c has the value: %d", c) // 输出：c has the value: 7
 }
 ```
 
@@ -469,7 +469,7 @@ func main() {
 在 ASCII 码表中，A 的值是 65，而使用 16 进制表示则为 41，所以下面的写法是等效的：
 
 ```go
-var ch byte = 65 或 var ch byte = ‘\x41’
+var ch byte = 65 或 var ch byte = '\x41'
 ```
 
 （`\x` 总是紧跟着长度为 2 的 16 进制数）
@@ -485,13 +485,13 @@ var ch byte = 65 或 var ch byte = ‘\x41’
 示例 4.12 [char.go](examples/chapter_4/char.go)
 
 ```go
-var ch int = ‘\u0041’
-var ch2 int = ‘\u03B2’
-var ch3 int = ‘\U00101234’
-fmt.Printf(“%d - %d - %d\n”, ch, ch2, ch3) // integer
-fmt.Printf(“%c - %c - %c\n”, ch, ch2, ch3) // character
-fmt.Printf(“%X - %X - %X\n”, ch, ch2, ch3) // UTF-8 bytes
-fmt.Printf(“%U - %U - %U”, ch, ch2, ch3) // UTF-8 code point
+var ch int = '\u0041'
+var ch2 int = '\u03B2'
+var ch3 int = '\U00101234'
+fmt.Printf("%d - %d - %d\n", ch, ch2, ch3) // integer
+fmt.Printf("%c - %c - %c\n", ch, ch2, ch3) // character
+fmt.Printf("%X - %X - %X\n", ch, ch2, ch3) // UTF-8 bytes
+fmt.Printf("%U - %U - %U", ch, ch2, ch3) // UTF-8 code point
 ```
 
 输出：