BOSTON — Rene Rancourt, like he has done so many times, walked onto the TD Garden ice to sing the Canadian and American national anthems before Wednesday night’s game between the Boston Bruins and Montreal Canadiens. But this night had a different feel. The emotion of the crowd, and Rancourt himself, clearly was heightened. That’s because the legendary national anthem singer will retire at the end of the season, the B’s announced Wednesday. Rancourt has been singing the “Star-Spangled Banner” and “O Canada” before Bruins games for more than 40 years, and he’s become a staple of not only the B’s culture, but also the community as well. NESN.com