finish part 2

Signed-off-by: Alex Chi <iskyzh@gmail.com>

mini-lsm-book/src/lsm-tutorial/week2-00-two-extremes-1.svg

@@ -8,7 +8,7 @@
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-  <g id="week2-00-two-extremes-1" stroke-opacity="1" fill-opacity="1" stroke-dasharray="none" stroke="none" fill="none">
+  <g id="week2-00-two-extremes-1" fill="none" stroke="none" fill-opacity="1" stroke-dasharray="none" stroke-opacity="1">
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