Fix the exemplary Jake diagram to match its description

The text following the diagram stated we traversed back to step 1, but the diagram accidentally showed step 2 as current.

Author: domenic

source

@@ -87307,8 +87307,8 @@ interface <dfn interface>BeforeUnloadEvent</dfn> : <span>Event</span> {
   history entries</span>, is the <dfn>Jake diagram</dfn>. A typical Jake diagram is the
   following:</p>
 
-  <!--https://domenic.github.io/jake-diagram-generator/#IWN1cnJlbnQgPSAyCnRvcAogIDAtMjogL3QtYSB8IGRvYzEKICAzOiAvdC1hI2ZvbyB8IGRvYzEKICA0OiAvdC1iCmZyYW1lc1swXQogIDA6IC9pLTAtYQogIDEtMzogL2ktMC1iCmZyYW1lc1sxXQogIDAtMTogL2ktMS1hCiAgMi0zOiAvaS0xLWIK -->
-  <table class="jake-diagram"><thead><tr><td></td><th class="step">0</th><th class="step">1</th><th class="step current">2</th><th class="step">3</th><th class="step">4</th></tr></thead><tbody><tr><th><code data-x="">top</code></th><td colspan="3" class="doc-0 current next-is-same-doc">/t-a</td><td colspan="1" class="doc-0 prev-is-same-doc">/t-a#foo</td><td colspan="1" class="doc-1">/t-b</td></tr><tr><th><code data-x="">frames[0]</code></th><td colspan="1" class="doc-2">/i-0-a</td><td colspan="3" class="doc-3 current">/i-0-b</td></tr><tr><th><code data-x="">frames[1]</code></th><td colspan="2" class="doc-4">/i-1-a</td><td colspan="2" class="doc-5 current">/i-1-b</td></tr></tbody></table>
+  <!--https://domenic.github.io/jake-diagram-generator/#IWN1cnJlbnQgPSAxCnRvcAogIDAtMjogL3QtYSB8IGRvYzEKICAzOiAvdC1hI2ZvbyB8IGRvYzEKICA0OiAvdC1iCmZyYW1lc1swXQogIDA6IC9pLTAtYQogIDEtMzogL2ktMC1iCmZyYW1lc1sxXQogIDAtMTogL2ktMS1hCiAgMi0zOiAvaS0xLWIK -->
+  <table class="jake-diagram"><thead><tr><td></td><th class="step">0</th><th class="step current">1</th><th class="step">2</th><th class="step">3</th><th class="step">4</th></tr></thead><tbody><tr><th><code data-x="">top</code></th><td colspan="3" class="doc-0 current next-is-same-doc">/t-a</td><td colspan="1" class="doc-0 prev-is-same-doc">/t-a#foo</td><td colspan="1" class="doc-1">/t-b</td></tr><tr><th><code data-x="">frames[0]</code></th><td colspan="1" class="doc-2">/i-0-a</td><td colspan="3" class="doc-3 current">/i-0-b</td></tr><tr><th><code data-x="">frames[1]</code></th><td colspan="2" class="doc-4 current">/i-1-a</td><td colspan="2" class="doc-5">/i-1-b</td></tr></tbody></table>
 
   <p>Here, each numbered column denotes a possible value for the traversable's <span
   data-x="tn-current-session-history-step">session history step</span>. Each labeled row depicts a