Add more linters to improve code readability (#19989)

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

routers/web/repo/branch.go

@@ -80,7 +80,7 @@ func Branches(ctx *context.Context) {
 	}
 	ctx.Data["Branches"] = branches
 	ctx.Data["DefaultBranchBranch"] = defaultBranchBranch
-	pager := context.NewPagination(int(branchesCount), setting.Git.BranchesRangeSize, page, 5)
+	pager := context.NewPagination(branchesCount, setting.Git.BranchesRangeSize, page, 5)
 	pager.SetDefaultParams(ctx)
 	ctx.Data["Page"] = pager
 

routers/web/repo/download.go

@@ -116,7 +116,7 @@ func getBlobForEntry(ctx *context.Context) (blob *git.Blob, lastModified time.Ti
 	}
 	blob = entry.Blob()
 
-	return
+	return blob, lastModified
 }
 
 // SingleDownload download a file by repos path

routers/web/repo/editor_test.go

@@ -70,9 +70,7 @@ func TestGetClosestParentWithFiles(t *testing.T) {
 	gitRepo, _ := git.OpenRepository(git.DefaultContext, repo.RepoPath())
 	defer gitRepo.Close()
 	commit, _ := gitRepo.GetBranchCommit(branch)
-	expectedTreePath := ""
-
-	expectedTreePath = "" // Should return the root dir, empty string, since there are no subdirs in this repo
+	var expectedTreePath string // Should return the root dir, empty string, since there are no subdirs in this repo
 	for _, deletedFile := range []string{
 		"dir1/dir2/dir3/file.txt",
 		"file.txt",

routers/web/repo/projects.go

@@ -105,7 +105,7 @@ func Projects(ctx *context.Context) {
 
 	numPages := 0
 	if count > 0 {
-		numPages = int((int(count) - 1) / setting.UI.IssuePagingNum)
+		numPages = (int(count) - 1/setting.UI.IssuePagingNum)
 	}
 
 	pager := context.NewPagination(total, setting.UI.IssuePagingNum, page, numPages)

routers/web/repo/view.go

@@ -353,7 +353,7 @@ func renderReadmeFile(ctx *context.Context, readmeFile *namedBlob, readmeTreelin
 
 	if markupType := markup.Type(readmeFile.name); markupType != "" {
 		ctx.Data["IsMarkup"] = true
-		ctx.Data["MarkupType"] = string(markupType)
+		ctx.Data["MarkupType"] = markupType
 		var result strings.Builder
 		err := markup.Render(&markup.RenderContext{
 			Ctx:          ctx,