Escape the string even when the condition of link_to_unless is not satisfied.
Added test for link_to_unless to make sure the result consistency.
Use Colspan in th Tags

Is it more suitable that using ```<th colspan="3">``` instead of three empty ```<th>```? It is simple, but what i am missing about it?

Change repetitive th tags to use colspan attribute

Update CHANGELOG.md

Update CHANGELOG.md
Merge pull request #10971 from dtaniwaki/escape_link_to_unless

Always escape the result of link_to_unless method
Merge pull request #10970 from sbagdat/patch-1

Use Colspan in th Tags