By Devik Jain and Amruta Khandekar (Reuters) -European shares gained on Friday marking an upbeat end to the week, helped by an initial boost after the British government’s turnaround on tax cuts, but this faded due to continued uncertainty about its fiscal stance. The region-wide STOXX 600 index closed up 0.6%, building on Thursday’s rally but was still off session highs hit immediately after British Prime Minister Liz Truss announced the scrapping of parts of the government’s fiscal programme. Truss fired her finance minister Kwasi Kwarteng and said Britain would retain plans to increase corp…