i18n: fix "% inside _()" problems Before this patch, "contrib/check-code.py" can't detect these problems, because the regexp pattern to detect "% inside _()" doesn't suppose the case that format string consists of multiple string components concatenated implicitly or explicitly, This patch does below for that regexp pattern to detect "% inside _()" problems in such case. - put "+" into separator part ("[ \t\n]") for explicit concatenation ("...." + "...." style) - enclose "component and separator" part by "(?:....)+" for concatenation itself ("...." "...." or "...." + "....")

i18n: fix "% inside _()" problems Before this patch, "contrib/check-code.py" can't detect these problems, because the regexp pattern to detect "% inside _()" doesn't suppose the case that the format string and "%" aren't placed in the same line. This patch replaces "\s" in that regexp pattern with "[ \t\n]" to detect "% inside _()" problems in such case. "[\s\n]" can't be used in this purpose, because "\s" is automatically replaced with "[ \t]" by "_preparepats()" and "\s" in "[]" causes nested "[]" unexpectedly.

merge: fix lack of "%s" in format string causing TypeError at runtime