See https://github.com/googleapis/google-cloud-php/issues/9193
`protoc` is generating the invalid class name `Object` when it should be prefixed with `PB` to prevent a conflict with PHP reserved words. I've submitted a fix for this in #27475
This PR introduces the script `php/update_reserved_words.sh` which updates the library in the **8 different classfiles** which all have various ways this logic is defined. Hopefully this makes these things easier for us to maintain in the future.
**NOTE**: prefixing constants with PB has been unnecessary since PHP 7, so we can and should open those up to every word but `class` in the next major version. I've added a comment so we (hopefully) don't forget
```sh
$ bash php/update_reserved_words.sh
Updated src/google/protobuf/compiler/php/names.cc
Updated php/ext/google/protobuf/names.c
Updated src/google/protobuf/compiler/php/php_generator.cc
Updated php/tests/proto/test_reserved_message_lower.proto
Updated php/tests/proto/test_reserved_message_upper.proto
Updated php/tests/proto/test_reserved_enum_lower.proto
Updated php/tests/proto/test_reserved_enum_upper.proto
Updated php/tests/proto/test_reserved_enum_value_lower.proto
Updated php/tests/proto/test_reserved_enum_value_upper.proto
Updated php/tests/GeneratedClassTest.php
Updated php/src/Google/Protobuf/Internal/GPBUtil.php
```
Closes#27456
COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/27456 from bshaffer:php-update-reserved-words 522d93f1c1
PiperOrigin-RevId: 962903274
addresses https://github.com/protocolbuffers/protobuf/issues/12714 by dumping more concise debug info for protobuf messages and repeated fields via the `serializeToJsonString` function. Additionally, message types which serialize into something other than an array (e.g. `Google\Protobuf\Value`, `Google\Protobuf\Timestamp`, etc) are handled in a special way to make their output consistent with other messages.
```php
$m = new Google\Protobuf\DoubleValue();
$m->setValue(1.5);
var_dump($m);
```
will output
```
object(Google\Protobuf\DoubleValue)#12 (1) {
["value"]=>
float(1.5)
}
```
Closes#12718
COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/12718 from bshaffer:php-add-debuginfo c40a6f91de
PiperOrigin-RevId: 574115431
