Feature: add limit option to cloneBlock

[moghwan]

Description

This PR adds a limit parameter to the cloneBlock function. This will help to minimize processing when the limit is needed for a bulk cloning operation, especially when there are multiple occurrences of the same block in the document.

example:

$templateProcessor = new TemplateProcessor('sample.docx');

// current
// This will clone all occurrences of the "block" in the document
$templateProcessor->cloneBlock('block', 3);

// improvement
// assuming we want to clone only the first occurrence of the "block":
$templateProcessor->cloneBlock('block', 3, true, false, null, 1);

Checklist:

• My CI is 🟢
• I have covered by unit tests my new code (check build/coverage for coverage report)
• I have updated the documentation to describe the changes
• I have updated the changelog

[coveralls]

coverage: 96.667% (-0.09%) from 96.757%
when pulling 9eea948 on moghwan:feat/add-limit-to-cloneblock
into 0ab0b49 on PHPOffice:master.

[moghwan]

hello @Progi1984, I've updated my branch with master, do my improvments require to update the unit test even all is green ? let me know if so!