fix: filter hard line wrapping from method summaries

[tkegan]

My company has a policy of hard wrapping lines including doc comments. This leads to broken listing class methods when generating documentation with phpdoc-md. This PR if accepted filters hard line wraps from method summaries in Clean\PhpDocMd\Markdown\ClassInfo which feels to me as if it is the correct place given existing separation of responsibilities. This change is sufficient for the code bases I work with though I could foresee it being insufficient for others. Included is also a change to the example BasicClass showing the issue is resolved.