better argument names for StringContains #7468

Job	Run time
Build LPython to WASM	2m 3s
LPython CI (3.10, ubuntu-latest)	1m 26s
Test CPython Interop (@pythoncall)	1m 8s
LPython CI (3.10, macos-latest)	2m 18s
Build Jupyter Kernel	51s
Check Debug build	1m 10s
LPython CI (3.10, windows-2019)	6m 35s
Run Integration tests with Python 3.9	1m 21s
Check Release build	1m 12s
Run Integration tests with Python 3.10	1m 13s
Run SymPy tests	1m 34s
Test LLVM 10	1m 5s
Run Integration tests with Python 3.11	1m 15s
Test LLVM 15	1m 12s
Run Integration tests with Python 3.12	1m 15s
Test PIP Installable Packages	1m 12s
Test LLVM 16	1m 15s
Upload Tarball	34s
	28m 39s

Provide feedback