Relying on the GET request issued first to fetch the file we want to
delete is not enough to avoid this error. If the file is deleted after
our GET request but before the DELETE request we'll get a NotFound error
that after all means that the file is already deleted, so it can be
safely ignored.

In Action View Overview guide, remove reference to custom helpers [ci skip]

Support multiple versions arguments for `gem` method of Generators

Delegate :rindex, :slice, :rotate(missing) to 'records'

Unify the internal source control .keep file name

Run CodeClimate with the latest Rubocop

Update RDOC_MAIN.rdoc

[ci skip]

Add documentation about template partial caching

Motivation:
  - #29423 surfaced some confusion about how template caching works when
  using partials across files with different mime types. This doc
  attempts to explain how this can be accomplished.

Fix `can't modify frozen String` error in `DatabaseTasks`

Without this, `db:structure:dump` task raises an error as follwing:

```
can't modify frozen String
activerecord/lib/active_record/tasks/sqlite_database_tasks.rb:77:in `run_cmd_error'
activerecord/lib/active_record/tasks/sqlite_database_tasks.rb:72:in `run_cmd'
activerecord/lib/active_record/tasks/sqlite_database_tasks.rb:52:in `structure_dump'
activerecord/lib/active_record/tasks/database_tasks.rb:219:in `structure_dump'
activerecord/lib/active_record/railties/databases.rake:279:in `block (3 levels) in <main>'
railties/lib/rails/commands/rake/rake_command.rb:23:in `block in perform'
railties/lib/rails/commands/rake/rake_command.rb:20:in `perform'
railties/lib/rails/command.rb:48:in `invoke'
railties/lib/rails/commands.rb:18:in `<main>'
```

Update activejob doc [ci skip]

Update Action Mailer doc [ci skip]

Update Active Storage docs [ci skip]

This is a partial revert of 07402aa1.

I also changed "cache-key" to "cache key" because "cache-key" appears
only once in the repo.

```
% git grep '\bcache-key\b' | wc -l
1

% git grep '\bcache key\b' | wc -l
28
```

I'm not sure this is the problem we're seeing on Travis (occasional
unexpected IOError exceptions), but it's worth a try.

Update Caching with Rails guide [ci skip]

Merge pull request #30451 from y-yagi/fix_cant_modify_forzen_string_error_in_dbconsole_with_sqlserver

Fix `can't modify frozen String` error in `DBConsole`

Without this, `dbconsole` raises an error as follwing:

```
RuntimeError: can't modify frozen String
    railties/lib/rails/commands/dbconsole/dbconsole_command.rb:79:in `start'
```

Added CHANGELOG for #30360 [ci skip]

Update Rails I18n API guide [ci skip]

Fix `can't modify frozen String` error in `DebugLocks`

Clarify that bulk option is supported only by MySQL

Fix indentation in the template for secrets

- Closes #30441

This fixes following warnings:

```
actionpack/lib/action_dispatch/middleware/debug_locks.rb:46: warning: shadowing outer local variable - threads
```

Without this, `DebugLocks` middleware raises an error as follwing:

```
Puma caught this error: can't modify frozen String (RuntimeError)
actionpack/lib/action_dispatch/middleware/debug_locks.rb:97:in `block in render_details'
actionpack/lib/action_dispatch/middleware/debug_locks.rb:64:in `each'
actionpack/lib/action_dispatch/middleware/debug_locks.rb:64:in `map'
actionpack/lib/action_dispatch/middleware/debug_locks.rb:64:in `render_details'
actionpack/lib/action_dispatch/middleware/debug_locks.rb:37:in `call'
railties/lib/rails/engine.rb:524:in `call'
```