sequencer: stop pretending that an assignment is a condition

In 3e81bccdf3 (sequencer: factor out todo command name parsing, 2019-06-27), a `return` statement was introduced that basically was a long sequence of conditions, combined with `&&`, except for the last condition which is not really a condition but an assignment. The point of this construct was to return 1 (i.e. `true`) from the function if all of those conditions held true, and also assign the `bol` pointer to the end of the parsed command. Some static analyzers are really unhappy about such constructs. And human readers are at least puzzled, if not confused, by seeing a single `=` inside a chain of conditions where they would have expected to see `==` instead and, based on experience, immediately suspect a typo. Let's help all of this by turning this into the more verbose, more readable form of an `if` construct that both assigns the pointer as well as returns 1 if all of the conditions hold true. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>