Fixed broken links in readme

[ktos]

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build or CI related changes
[ x ] Documentation content changes
[ ] Sample app changes
[ ] Other... Please describe:

What is the current behavior?

Link to PrinterHelper was obviously wrong, resulting in 404 and should be PrintHelper.

However, other links to www.uwpcommunitytoolkit.com were randomly (sometimes, not always) giving me 404, while there is no such problem with docs.uwpcommunitytoolkit.com.

PR Checklist

Please check if your PR fulfills the following requirements:

• Tested code with current supported SDKs
• [ x ] Docs have been added / updated (for bug fixes / features)
• Sample in sample app has been added / updated (for bug fixes / features)
• Tests for the changes have been added (for bug fixes / features) (if applicable)

What is the new behavior?

Links are correct :)

Does this PR introduce a breaking change?

[ ] Yes
[ x ] No

Other information

[dnfclas]

@ktos,
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.NET Foundation Pull Request Bot

[nmetulev]

Thank you for fixing these