US Irritable Bowel Syndrome Treatment Market to 2027 - Country Analysis and Forecasts by Type (IBS with Diarrhea (IBS-D), IBS with Constipation (IBS-C), Mixed IBS (IBS-M)); Product (Rifaximin, Eluxadoline, Lubiprostone, Linaclotide, Others); Distribution Channel (Hospital Pharmacies, Drug Stores and Retail Pharmacies, Online Pharmacies)