docs: fix typos (#1665)

* docs: fix typos

* typos: fix typos found by `codespell` across the codebase

* docs: fix `macOS` spelling

* docs: fix `authentification` terminology

"Authentification" is not a thing.

* docs: fix `localhost` typo in example link

* typos: fix in-code typos

These are potentially higher risk, but no other mentions of these typos
show up in the codebase.

frontend/api/class-interfaces/backups.ts

@@ -14,7 +14,7 @@ const routes = {
 };
 
 export class BackupAPI extends BaseAPI {
-  /** Returns a list of avaiable .zip files for import into Mealie.
+  /** Returns a list of available .zip files for import into Mealie.
    */
   async getAll() {
     return await this.requests.get<AllBackups>(routes.backupsAvailable);

frontend/api/class-interfaces/user-registration.ts

@@ -8,7 +8,7 @@ const routes = {
 };
 
 export class RegisterAPI extends BaseAPI {
-  /** Returns a list of avaiable .zip files for import into Mealie.
+  /** Returns a list of available .zip files for import into Mealie.
    */
   async register(payload: CreateUserRegistration) {
     return await this.requests.post<any>(routes.register, payload);