I took this questions to mean "Are good programmers more likely to be good musicians than non-programmers?" because the real question is a bit trivial (as one comment indicates) and I thought I could tell that this was what Sklivvz wanted to know from his own answer.
The most parsimonious explanation for this is likely to be the general factor of mental ability.
Here is a study by Deary, Strand, Smith, Fernandes (2007) on the relation of IQ tests to achievement in different school subjects in >70000 English school children.
The correlation of g with music was .54, with Information Technology it was .48, with math it was .77.
Here's another much smaller study:
Multiple regression analysis revealed that the best single predictor of music achievement was the academic achievement test.
So, in summary, smart people are good at music, maths, programming and other complicated stuff.
There is no specific reason to believe that there is a correlation between programming and music that goes beyond the one expected on the basis of the general factor underlying both, if experience with other abilities is any guide.
There is also no basis to recommend to guitarists to start programming or to programmers to start playing the guitar, at least not if they want to do this to improve on their "main game" -> cognitive training is usually highly specific (practicing the guitar makes you good with the guitar, not with git) and it's unlikely that this relationship is the exception.
That is why the Jaeggi study is the one that most researchers want to see replicated at Psychfiledrawer.com (in fact there have been several nonreplications already).