mergeQueryHs() not handling OR queries properly #558
Description
In [2]: Chem.MolToSmarts(Chem.MolFromSmarts('[#6]-[#1,#6]',mergeHs=True))
Out[2]: '[#6]-[#1,#6]'
That could, theoretically, produce [#6;!H0,$([#6]-[#6])]. The query restructuring involved is doable, but non-trivial.
The real fun will come with cases like [#6](-[#1,#6])-[#1,#6], which would need to be converted to: [#6;!H0&!H1,$([#6&H1]-[#6]),$([#6](-[#6])-[#6])]
