Unnecessary Heredoc

If no interpolation or expressions are used in the body of a heredoc, nowdoc syntax should be used instead.

Valid: Using nowdoc syntax for a text string without any interpolation or expressions.

$nowdoc = <em><<<'EOD'</em> some text EOD;

Invalid: Using heredoc syntax for a text string without any interpolation or expressions.

$heredoc = <em><<<EOD</em> some text EOD;

Valid: Using heredoc syntax for a text string containing interpolation or expressions.

$heredoc = <em><<<"EOD"</em> some $text EOD;

Invalid: Using heredoc syntax for a text string without any interpolation or expressions.

$heredoc = <em><<<"EOD"</em> some text EOD;