Could tejano music have picked a more jovial, warmhearted ambassador? Leonard “Flaco” Jiménez, who died Thursday at the age of 86, was something more than simply a master accordion player and an exceptionally versatile session musician: He was a steward of the joy his music brought to others and the power it had to bring people together.“One way to look at it: Leonardo ‘Flaco’ Jimenez is our ‘Satchmo,’ the Alamo City’s Louis Armstrong,” Hector Saldaña wrote in 2019. “Both men pioneered distinct musical forms tied to their region, culture, race and ethnicity—and brought it to the world. Armstrong did it with his trumpet; Jimenez with a squeezebox.”From the start, it seemed that Jiménez’s eventual career in music was inevitable. His grandfather Patricio Jiménez played accordion,…