[css-grid-1] Format, add indentation

[jiangying000]

For better view

[dontcallmedom]

Marked as non substantive for IPR from ash-nazg.

[tabatkins]

The space-based indentation is intentional and correct, to line up the strings with those on the preceding line.

[jiangying000]

The space-based indentation is intentional and correct, to line up the strings with those on the preceding line.

Yes, I didn't change any of the space-based indentations, just add a tab inside whole block.