Improve error messages for ContainSubtree (fluentassertions#36)

* Improve error messages for ContainSubtree
* Also require strict order for elements in an array when checking subtree

Update to FluentAssertions 5.10.2 (fluentassertions#35)

* Update to FluentAssertions 5.10.2

This update reveals a mismatch in escaping new line characters.
Fixed by not replacing new line characters in JSON documents any more.

* fixup! Update to FluentAssertions 5.10.2

Merge pull request fluentassertions#34 from ronaldkroon/Improve_BeEqu…

…ivalentTo_error_messages

Improve BeEquivalentTo error messages

Add placeholder escaping in BeEquivalentTo message (fluentassertions#33)

* Added placeholder escaping for `difference` in BeEquivalentTo message creation (fluentassertions#32)

* Add expected message to test

Merge pull request fluentassertions#30 from ronaldkroon/Improve_error…

…_messages

Improve error messages

Add BeValidJson for checking strings (fluentassertions#29)

* Add BeValidJson for checking strings

It also allows consecutive checks on the parsed JSON using the Which
property.

The check does not limit the valid values to objects and arrays because
of reasons explained here:
https://stackoverflow.com/questions/7487869/is-this-simple-string-considered-valid-json

Fixed the URLs in the package

Merge pull request fluentassertions#19 from dennisdoomen/Merge50

Merging 5.0 to master

Added `ContainSubtree` constraint (fluentassertions#16)

See fluentassertions#6

Upgraded dependency to Fluent Assertions 5.0 RC2 (fluentassertions#14)