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.
(cherry picked from commit bab58480bc32323c6124c02bdf086b5de1843df0)