PHP: Added folding for heredoc and nowdoc

[troizet]

In this PR:

• Added folding for heredoc and nowdoc
• Fixed test FoldingTest
• Added new tests in FoldingTest

Example:

<?php

echo <<<HEREDOC
    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
    Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
    Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
    Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
HEREDOC;


echo <<<'NOWDOC'
    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
    Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
    Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
    Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
NOWDOC;

Before:

After:

[troizet]

@mbien Thanks for the tip. I've made the corrections.

[tmysik]

Thank you for your work.

[matthiasblaesing]

@troizet the git commit message should have the structure:

• first line is summary of the changes
• empty line
• detailed info about the changes (if necessary)

Would you mind updating to something along the lines of this?

Added folding for heredoc and nowdoc

Additionally:
- Fixed test FoldingTest
- Added new tests in FoldingTest

[troizet]

@matthiasblaesing Updated the commit message.

[matthiasblaesing]

@troizet thanks for your work!