select: move to common, fix placeholders

[acuteenvy]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The PR title conforms to the recommended templates.

This PR implements the fix from #12445 (${{{fruits[@]}}} will be rendered as ${fruits[@]} ), removes redundant braces ({{x}} {{y}} is rendered exactly the same as {{x y}}) and moves select to common, because Bash is not Linux-specific.

Closes #12445.

[kbdharun]

LGTM, thanks for the fix.