filemerge: use only the first line of the generated conflict marker for safety Before this patch, with careless configuration (missing '|firstline' filtering for '{desc}' keyword, for example), '[ui] mergemarkertemplate' can make conflict markers multiple lines. For ordinary users, advantage of allowing '[ui] mergemarkertemplate' to generate multiple lines for customizing seems to be less than advantage of disallowing it for safety. This patch uses only the first line of the conflict marker generated from '[ui] mergemarkertemplate' configuration for safety.

progress: use 'encoding.colwidth' to get column width of items correctly Before this patch, 'progress' extension applies 'len' on byte sequence to get column width of it, but it causes incorrect result, when length of byte sequence and columns in display are different from each other in multi-byte characters. This patch uses 'encoding.colwidth' to get column width of items in output line correctly, even if it contains multi-byte characters.

progress: use 'encoding.trim' to trim items in output line correctly Before this patch, 'progress' extension trims items in output line by directly slicing byte sequence, but it may split at intermediate multi-byte sequence. This patch uses 'encoding.trim' to trim items in output line correctly, even if it contains multi-byte characters.