appview,hook,knotserver: set charset=utf-8 for all text/plain responses

Signed-off-by: Anirudh Oppiliappan <[e-mail]>

appview/pulls/pulls.go

···
 		}
 	}
 
-	w.Header().Set("Content-Type", "text/plain")
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 	w.Write([]byte(pull.Submissions[roundIdInt].Patch))
 }
 

appview/repo/repo.go

···
 		return
 	}
 
-	w.Header().Set("Content-Type", "text/plain")
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 	w.Write([]byte(result.Contents))
 	return
 }

hook/hook.go

···
 		return fmt.Errorf("failed to create request: %w", err)
 	}
 
-	req.Header.Set("Content-Type", "text/plain")
+	req.Header.Set("Content-Type", "text/plain; charset=utf-8")
 	req.Header.Set("X-Git-Dir", gitDir)
 	req.Header.Set("X-Git-User-Did", userDid)
 	req.Header.Set("X-Git-User-Handle", userHandle)

knotserver/handler.go

···
 		}
 	}
 
-	w.Header().Set("Content-Type", "text/plain")
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 	fmt.Fprintf(w, "knotserver/%s", version)
 }