t3lib_div CGL Cleanup: Missing spaces around string concatenator
t3lib_div does absolutely not match the current CGL. This issue is intended be focused on one particular rule of CGL: "String concatenation operator must be surrounded by spaces".
This issue/RFC/patch intentionally ignores other violations of the CGL, because this would be too much for one RFC. So the modified lines still contain violations like missing spaces after comma and so on.
(issue imported from #M13729)