bugfix: clear selection when clicking above or below lines

Matt Wynne pointed out that snap.love would crash when a node went off
screen. While debugging it I noticed that selection1 was being set when
it shouldn't be.

Turns out I introduced a bug when I fixed the inscript bug back in June
(commit 9656e137742). One invariant I want to preserve is: selection1
should be unset after a mouse click (press and release without
intervening drag). This invariant was violated in my bugfix back in
June. I was concerned only with selection back then, and I didn't
realize I was breaking the mouse click case (in a fairly subtle way; you
can have selection set, and when it's set identically to the cursor
everything looks the same).

I think there might still be an issue in snap.love after this fix. I
noticed screen_bottom1.pos was nil, and as far as I recall that should
never happen.

1 files changed, 1 insertions, 0 deletions

diff --git a/text_tests b/text_tests
index f39d47e..2a31131 100644
--- a/text_tests
+++ b/text_tests
@@ -23,6 +23,7 @@ click on wrapping line rendered from partway at top of screen
 click past end of wrapping line
 click past end of wrapping line containing non ascii
 click past end of word wrapping line
+click below final line does nothing
 
 # cursor movement
 move left