docs: fix IGA section for current sources
docs: fix IGA section for current sources

rc/sfepy,sfepy/sfepy,RexFuzzle/sfepy,lokik/sfepy,sfepy/sfepy,vlukes/sfepy,sfepy/sfepy,rc/sfepy,BubuLK/sfepy,RexFuzzle/sfepy,RexFuzzle/sfepy,vlukes/sfepy,rc/sfepy,lokik/sfepy,BubuLK/sfepy,lokik/sfepy,vlukes/sfepy,lokik/sfepy,BubuLK/sfepy,RexFuzzle/sfepy