set tab size

Open username-removed-1408190 requested to merge gucong3000/gitlab-ee:patch-3 into master

What does this MR do?

change tab size of views of search and diffs

Are there points in the code the reviewer needs to double check?

Browser compatible.

Why was this MR needed?

in the views of search and diffs, tab width is too wide, and in most IDEs, its width is always 4, not 8.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

What are the relevant issue numbers?

Edited by username-removed-1408190