Add codespell support and fix a good number of typos with its help (#3270)

More about codespell: https://github.com/codespell-project/codespell .

I personally introduced it to dozens if not hundreds of projects already and so far only positive feedback.

```
❯ grep lint-spell Makefile
	@echo " - lint-spell                       lint spelling"
	@echo " - lint-spell-fix                   lint spelling and fix issues"
lint: lint-frontend lint-backend lint-spell
lint-fix: lint-frontend-fix lint-backend-fix lint-spell-fix
.PHONY: lint-spell
lint-spell: lint-codespell
.PHONY: lint-spell-fix
lint-spell-fix: lint-codespell-fix
❯ git grep lint- -- .forgejo/
.forgejo/workflows/testing.yml:      - run: make --always-make -j$(nproc) lint-backend checks-backend # ensure the "go-licenses" make target runs
.forgejo/workflows/testing.yml:      - run: make lint-frontend
```
so how would you like me to invoke `lint-codespell` on CI? (without that would be IMHO very suboptimal and let typos sneak in)

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/3270
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>
Co-authored-by: Yaroslav Halchenko <debian@onerussian.com>
Co-committed-by: Yaroslav Halchenko <debian@onerussian.com>

routers/api/actions/artifacts.go

@@ -301,7 +301,7 @@ func (ar artifactRoutes) uploadArtifact(ctx *ArtifactContext) {
 	})
 }
 
-// comfirmUploadArtifact comfirm upload artifact.
+// comfirmUploadArtifact confirm upload artifact.
 // if all chunks are uploaded, merge them to one file.
 func (ar artifactRoutes) comfirmUploadArtifact(ctx *ArtifactContext) {
 	_, runID, ok := validateRunID(ctx)

routers/api/actions/runner/interceptor.go

@@ -36,7 +36,7 @@ var withRunner = connect.WithInterceptors(connect.UnaryInterceptorFunc(func(unar
 		uuid := request.Header().Get(uuidHeaderKey)
 		token := request.Header().Get(tokenHeaderKey)
 		// TODO: version will be removed from request header after Gitea 1.20 released.
-		// And Gitea will not try to read version from reuqest header
+		// And Gitea will not try to read version from request header
 		version := request.Header().Get(versionHeaderKey)
 
 		runner, err := actions_model.GetRunnerByUUID(ctx, uuid)
@@ -53,7 +53,7 @@ var withRunner = connect.WithInterceptors(connect.UnaryInterceptorFunc(func(unar
 		cols := []string{"last_online"}
 
 		// TODO: version will be removed from request header after Gitea 1.20 released.
-		// And Gitea will not try to read version from reuqest header
+		// And Gitea will not try to read version from request header
 		version, _ = util.SplitStringAtByteN(version, 64)
 		if !util.IsEmptyString(version) && runner.Version != version {
 			runner.Version = version

routers/api/actions/runner/runner.go

@@ -162,7 +162,7 @@ func (s *Service) FetchTask(
 
 	if tasksVersion != latestVersion {
 		// if the task version in request is not equal to the version in db,
-		// it means there may still be some tasks not be assgined.
+		// it means there may still be some tasks not be assigned.
 		// try to pick a task for the runner that send the request.
 		if t, ok, err := pickTask(ctx, runner); err != nil {
 			log.Error("pick task failed: %v", err)

routers/api/packages/README.md

@@ -19,7 +19,7 @@ The package registry code is divided into multiple modules to split the function
 
 ## Models
 
-Every package registry implementation uses the same underlaying models:
+Every package registry implementation uses the same underlying models:
 
 | Model | Description |
 | - | - |

routers/api/v1/org/team.go

@@ -805,7 +805,7 @@ func SearchTeam(ctx *context.APIContext) {
 		ListOptions: listOptions,
 	}
 
-	// Only admin is allowd to search for all teams
+	// Only admin is allowed to search for all teams
 	if !ctx.Doer.IsAdmin {
 		opts.UserID = ctx.Doer.ID
 	}

routers/api/v1/repo/git_ref.go

@@ -33,7 +33,7 @@ func GetGitAllRefs(ctx *context.APIContext) {
 	//   required: true
 	// responses:
 	//   "200":
-	// #   "$ref": "#/responses/Reference" TODO: swagger doesnt support different output formats by ref
+	// #   "$ref": "#/responses/Reference" TODO: swagger doesn't support different output formats by ref
 	//     "$ref": "#/responses/ReferenceList"
 	//   "404":
 	//     "$ref": "#/responses/notFound"
@@ -66,7 +66,7 @@ func GetGitRefs(ctx *context.APIContext) {
 	//   required: true
 	// responses:
 	//   "200":
-	// #   "$ref": "#/responses/Reference" TODO: swagger doesnt support different output formats by ref
+	// #   "$ref": "#/responses/Reference" TODO: swagger doesn't support different output formats by ref
 	//     "$ref": "#/responses/ReferenceList"
 	//   "404":
 	//     "$ref": "#/responses/notFound"

routers/api/v1/repo/issue.go

@@ -411,8 +411,8 @@ func ListIssues(ctx *context.APIContext) {
 	}
 
 	var labelIDs []int64
-	if splitted := strings.Split(ctx.FormString("labels"), ","); len(splitted) > 0 {
-		labelIDs, err = issues_model.GetLabelIDsInRepoByNames(ctx, ctx.Repo.Repository.ID, splitted)
+	if split := strings.Split(ctx.FormString("labels"), ","); len(split) > 0 {
+		labelIDs, err = issues_model.GetLabelIDsInRepoByNames(ctx, ctx.Repo.Repository.ID, split)
 		if err != nil {
 			ctx.Error(http.StatusInternalServerError, "GetLabelIDsInRepoByNames", err)
 			return

routers/api/v1/repo/issue_subscription.go

@@ -138,7 +138,7 @@ func setIssueSubscription(ctx *context.APIContext, watch bool) {
 		return
 	}
 
-	// If watch state wont change
+	// If watch state won't change
 	if current == watch {
 		ctx.Status(http.StatusOK)
 		return