Do not skip space at start of row (fixes #8947, #8838)

Do not skip space at start of row (fixes #8947, #8838)

TextMetrics::getColumnNearX (x -> pos translation) has special code to
ignore spaces at the beginning of a row, but neither the display code
nor TextMetrics::cursorX (pos->x translation) follow this logic. One
might argue that spaces should actually be ignored (like LaTeX does),
but this leads to UI issues and is probably too difficult to
implement.