fix unhandled errors and update code comments to help the IDEs (#2128)

* fix unhandled errors

* fix unhandled error in cache package test

* omit variable type

* omit variable type

* rename variable because collide with the imported package name

* handle file error on closing

* fix unhandled in common_linux.go

* fix unhandled errors in helpers_test.go

* fix unhandled errors in listen_test.go

* remove unused parameter in emptyHandler method

* refactor path.go

* unhandled error in hooks test

* fix unhandled errors in app_test.go

* fix unhandled errors in ctx_test.go

* ✨ fix unhandled errors in helpers_test.go

* revert app_test.go

* remove redundant parentheses and update comments

* update code comment for helping ide

* update code comment for helping ide

* fix unhandled error in app_test.go

* update code comments for helping IDEs

* fix unhandled errors in app_test.go

* update code comment for helping the IDEs

app_test.go

@@ -1343,7 +1343,10 @@ func Test_App_ReadTimeout(t *testing.T) {
 
 		conn, err := net.Dial(NetworkTCP4, "127.0.0.1:4004")
 		utils.AssertEqual(t, nil, err)
-		defer conn.Close()
+		defer func(conn net.Conn) {
+			err := conn.Close()
+			utils.AssertEqual(t, nil, err)
+		}(conn)
 
 		_, err = conn.Write([]byte("HEAD /read-timeout HTTP/1.1\r\n"))
 		utils.AssertEqual(t, nil, err)
@@ -1375,7 +1378,10 @@ func Test_App_BadRequest(t *testing.T) {
 		time.Sleep(500 * time.Millisecond)
 		conn, err := net.Dial(NetworkTCP4, "127.0.0.1:4005")
 		utils.AssertEqual(t, nil, err)
-		defer conn.Close()
+		defer func(conn net.Conn) {
+			err := conn.Close()
+			utils.AssertEqual(t, nil, err)
+		}(conn)
 
 		_, err = conn.Write([]byte("BadRequest\r\n"))
 		utils.AssertEqual(t, nil, err)

error.go

@@ -7,7 +7,7 @@ import (
 )
 
 type (
-	// Conversion error exposes the internal schema.ConversionError for public use.
+	// ConversionError Conversion error exposes the internal schema.ConversionError for public use.
 	ConversionError = schema.ConversionError
 	// UnknownKeyError error exposes the internal schema.UnknownKeyError for public use.
 	UnknownKeyError = schema.UnknownKeyError