[ast] better display of string matrices
https://bugzilla.scilab.org/show_bug.cgi?id=16192
example:
--> x=["Mercury","Gemini","Apollo";"Skylab ABCDEF","Skylab B","ISS"]
x =
"Mercury" "Gemini" "Apollo"
"Skylab ABCDEF" "Skylab B" "ISS"
restored natural wrapping for very long strings, which allows direct
selection in console:
--> x="";for i=1:400,x=x+string(modulo(i,10)); end
--> x
x =
"123456789012345678901234567890123456789012345678901234567890123456789
012345678901234567890123456789012345678901234567890123456789012345678901
234567890123456789012345678901234567890123456789012345678901234567890123
456789012345678901234567890123456789012345678901234567890123456789012345
678901234567890123456789012345678901234567890123456789012345678901234567
8901234567890123456789012345678901234567890"
Change-Id: I0103c8e52e4476c446f28a79de217532adc06ab0