docs/understanding/concepts.rst: Doc tweaks
docs/understanding/concepts.rst: Doc tweaks

mderaldo/tsuru,Endika/tsuru,tsuru/tsuru,hcxiong/tsuru,hugoantunes/tsuru,4eek/tsuru,guilhermebr/tsuru,firebitsbr/tsuru,jblancett/tsuru,kgrvamsi/tsuru,ggarnier/tsuru,tsuru/tsuru,hugoantunes/tsuru,hcxiong/tsuru,cgvarela/tsuru,cezarsa/tsuru,guilhermebr/tsuru,tuxmonteiro/tsuru,gciotta/tsuru,ArxdSilva/tsuru,ArxdSilva/tsuru,gwmoura/tsuru,ArxdSilva/tsuru,gciotta/tsuru,kgrvamsi/tsuru,guilhermebr/tsuru,gwmoura/tsuru,mderaldo/tsuru,firebitsbr/tsuru,cgvarela/tsuru,ArxdSilva/tsuru,tsuru/tsuru,guilhermebr/tsuru,kgrvamsi/tsuru,RichardKnop/tsuru,gciotta/tsuru,hcxiong/tsuru,RichardKnop/tsuru,4eek/tsuru,cezarsa/tsuru,4eek/tsuru,mderaldo/tsuru,cezarsa/tsuru,jblancett/tsuru,jblancett/tsuru,ggarnier/tsuru,RichardKnop/tsuru,Endika/tsuru,gwmoura/tsuru,ggarnier/tsuru,tsuru/tsuru,tuxmonteiro/tsuru,firebitsbr/tsuru,cezarsa/tsuru,Endika/tsuru,cgvarela/tsuru,tuxmonteiro/tsuru,ggarnier/tsuru