fixing mailer previews for apps with globbing route
Test coverage for ActiveJob generator
Fix grammar of sentence in Reflection documentation
Merge pull request #17959 from eileencodes/fix-grammar-on-reflection

Fix grammar of sentence in Reflection documentation [ci skip]
minor sentences fixes
Make error message clearer that :on requires a symbol, not a string

The validation added in 5a3dc8092d19c816b0b1203945639cb91d065847 will
reject values for the `:on` option for after_commit and after_rollback
callbacks that are string values like `"create"`.

However, the error message says ":on conditions for after_commit and
after_rollback callbacks have to be one of create,destroy,update". That
looks like a string value *would* be valid.

This commit changes the error message to say ":on conditions for
after_commit and after_rollback callbacks have to be one of [:create,
:destroy, :update]", making it clearer that symbols are required.
Merge pull request #17963 from neerajdotname/wordsmitthing

minor sentences fixes
Add note to Store about uniqueness validation (#17954) [skip ci]
Merge pull request #17953 from kirs/test-activejob-generator

Test coverage for ActiveJob generator
Merge pull request #17966 from mikechau/update-ar-store-validation-documentation

Add note to Store about uniqueness validation (#17954) [skip ci]
Fix type case of "validations" and word-wrap from #17954 [ci skip]
add brackets around attribute_name

since 'attr_name_will_change!' is not an actual method it should
be clearer that you have to insert the attribute name as in line 104

[ci skip]
Merge pull request #17969 from tiii/add-brackets-around-attribute_name

add brackets around attribute_name [ci skip]
Merge pull request #17896 from GBH/globbing_route_mailer_preview

fixing mailer previews for apps with globbing route
Merge pull request #17964 from carols10cents/improve-after-commit-argumenterror-message

Make error message clearer that :on requires a symbol, not a string
Only check that it is a Rails application once

Also avoid using try since is_a? is faster for this case.