rubocops/shared/url_helper: tweak SourceForge handling #30914

Job	Run time
syntax	1m 9s
vendored gems	41s
tap syntax	59s
formula audit	44s
cask audit	53s
test default formula (Ubuntu 22.04)	44s
tests (online)	55s
test default formula (Ubuntu 20.04)	43s
tests (generic OS)	56s
test default formula (macOS 13 x86_64)	54s
tests (Ubuntu 22.04)	53s
test default formula (macOS 15 arm64)	55s
tests (Ubuntu 20.04)	55s
update-test (Ubuntu 22.04)	17s
tests (macOS 13 x86_64)	44s
tests (macOS 15 arm64)	52s
update-test (macOS)	32s
	13m 46s

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