[giac] change from using 1∡2 to ggb_ang(1,2) as syntax for polar (1;2) [part 2, see r25945]

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25954 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e