Simplify code in AS json encoder
replace regexp global in #url_for
Modify TimeWithZone#as_json to return 3DP of sub-second accuracy by default, since it's allowed by the spec and is very useful.
Fix file name in document [ci skip]

This file was renamed in c8a25386d.
Fix article for generator name

Use 'some' instead of 'a/an'.
Fixing the examples for button_to

The examples do not generate the output they intend to due to not explicitly declaring the hash separations. This causes it to be treated as one parameter instead of the intended two parameters.
Merge pull request #9128 from jamesotron/iso8601-sub-second-accuracy

Modify TimeWithZone#as_json to return 3DP of sub-second accuracy.
Update changelog from #9128 with author name

And improve AS changelog a bit [ci skip]
Change Class#subclasses doc example
Add some tests to enumerate how extensions should be stored in the schema output
improve tests to check for existence of extensions method, and skip testing dumped extensions if they are unsupported by the database
add ActiveRecord::AbstractAdapter#extensions and ActiveRecord::ConnectionAdapters::PostgreSQLAdapter#extensions to allow dumping of enabled extensions to schema.rb, add ActiveRecord::SchemaDumper#extensions to dump extensions to schema.rb
Merge pull request #9203 from jaggederest/dumping_pgsql_extensions

Adding database extension support to schema.rb
Add changelog entry for #9203 about schema dumper with db extensions

[ci skip]
Call super to use the abstract adapter implementation instead
Fix indentation of extensions in schema
Add blank line after extensions to separate from tables in schema
Do not print anything related to extensions when they don't none exist

When extensions are supported but there's no one enabled in the
database, we should not print anything related to them in schema.rb.
Run schema dumper extensions without creating real extensions

There is no need to create the extension in the database just to test if
it's dumped, we can stub that instead.
active_record: Quote numeric values compared to string columns.