update: warn message

Signed-off-by: karamaru-alpha <mrnk3078@gmail.com>

README.md

@@ -6,13 +6,13 @@ cf. [Fixing For Loops in Go 1.22](https://go.dev/blog/loopvar-preview)
 ## Example
 ```go
 for i, v := range []int{1, 2, 3} {
-    i := i // The loop variable "i" doesn't need to be copied
-    v := v // The loop variable "v" doesn't need to be copied
+    i := i // It's unnecessary to copy the loop variable "i"
+    v := v // It's unnecessary to copy the loop variable "v"
     _, _ = i, v
 }
 
 for i := 1; i <= 3; i++ {
-    i := i // The loop variable "i" doesn't need to be copied``
+    i := i // It's unnecessary to copy the loop variable "i"
     _ = i
 }
 ```

copyloopvar.go

@@ -66,7 +66,7 @@ func checkRangeStmt(pass *analysis.Pass, rangeStmt *ast.RangeStmt) {
 			}
 			pass.Report(analysis.Diagnostic{
 				Pos:     assignStmt.Pos(),
-				Message: fmt.Sprintf(`The loop variable "%s" doesn't need to be copied`, right.Name),
+				Message: fmt.Sprintf(`It's unnecessary to copy the loop variable "%s"`, right.Name),
 			})
 		}
 	}
@@ -104,7 +104,7 @@ func checkForStmt(pass *analysis.Pass, forStmt *ast.ForStmt) {
 			}
 			pass.Report(analysis.Diagnostic{
 				Pos:     assignStmt.Pos(),
-				Message: fmt.Sprintf(`The loop variable "%s" doesn't need to be copied`, right.Name),
+				Message: fmt.Sprintf(`It's unnecessary to copy the loop variable "%s"`, right.Name),
 			})
 		}
 	}

testdata/src/a/main.go

@@ -2,20 +2,20 @@ package a
 
 func f() {
 	for i, v := range []int{1, 2, 3} {
-		i := i  // want `The loop variable "i" doesn't need to be copied`
-		_v := v // want `The loop variable "v" doesn't need to be copied`
+		i := i  // want `It's unnecessary to copy the loop variable "i"`
+		_v := v // want `It's unnecessary to copy the loop variable "v"`
 		_ = i
 		_ = _v
 	}
 
 	for i := 1; i <= 3; i++ {
-		i := i // want `The loop variable "i" doesn't need to be copied`
+		i := i // want `It's unnecessary to copy the loop variable "i"`
 		_ = i
 	}
 
 	for i, j := 1, 1; i+j <= 3; i++ {
-		i := i       // want `The loop variable "i" doesn't need to be copied`
-		j, _ := j, 1 // want `The loop variable "j" doesn't need to be copied`
+		i := i       // want `It's unnecessary to copy the loop variable "i"`
+		j, _ := j, 1 // want `It's unnecessary to copy the loop variable "j"`
 		_, _ = i, j
 	}
 }