Initializes @iter to the start of the given line.
If @line_number is greater than or equal to the number of lines in the @buffer, the end iterator is returned.
iterator to initialize
line number counting from 0
whether the exact position has been found
See Implementation
Initializes @iter to the start of the given line.
If @line_number is greater than or equal to the number of lines in the @buffer, the end iterator is returned.