let generic datastore error include func name (#2041)

error logs like:
```
{"level":"warn","error":"sql: no rows in result set","time":"2023-07-25T21:29:56Z"}
```

have to less context to be helpfull.
this will cange it as the message now looks like:

```
{"level":"warn","error":"GetPipelineLast: sql: no rows in result set", "time":"2023-07-27T02:54:25+02:00"}
```

server/store/datastore/helper.go

@@ -15,6 +15,10 @@
 package datastore
 
 import (
+	"fmt"
+	"runtime"
+	"strings"
+
 	"xorm.io/xorm"
 
 	"github.com/woodpecker-ci/woodpecker/server/model"
@@ -23,22 +27,26 @@ import (
 
 // wrapGet return error if err not nil or if requested entry do not exist
 func wrapGet(exist bool, err error) error {
-	if err != nil {
-		return err
-	}
 	if !exist {
-		return types.RecordNotExist
+		err = types.RecordNotExist
+	}
+	if err != nil {
+		// we only ask for the function's name if needed, as it's not as preformatted as to just execute it
+		fnName := callerName(2)
+		return fmt.Errorf("%s: %w", fnName, err)
 	}
 	return nil
 }
 
 // wrapDelete return error if err not nil or if requested entry do not exist
 func wrapDelete(c int64, err error) error {
-	if err != nil {
-		return err
-	}
 	if c == 0 {
-		return types.RecordNotExist
+		err = types.RecordNotExist
+	}
+	if err != nil {
+		// we only ask for the function's name if needed, as it's not as preformatted as to just execute it
+		fnName := callerName(2)
+		return fmt.Errorf("%s: %w", fnName, err)
 	}
 	return nil
 }
@@ -55,3 +63,16 @@ func (s storage) paginate(p *model.ListOptions) *xorm.Session {
 	}
 	return s.engine.Limit(p.PerPage, p.PerPage*(p.Page-1))
 }
+
+func callerName(skip int) string {
+	pc, _, _, ok := runtime.Caller(skip)
+	if !ok {
+		return ""
+	}
+	fnName := runtime.FuncForPC(pc).Name()
+	pIndex := strings.LastIndex(fnName, ".")
+	if pIndex != -1 {
+		fnName = fnName[pIndex+1:]
+	}
+	return fnName
+}