ZIP 208: "at least" -> "greater than". refs ZcashFoundation/zebra#1276

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

zip-0208.html

@@ -112,7 +112,7 @@
                 <p>Note that the change in AveragingWindowTimespan(height) takes effect immediately when calculating the target difficulty starting from the block at the Blossom activation height, even though the difficulty of the preceding PoWAveragingWindow blocks will have been adjusted using the pre-Blossom target spacing. Therefore it is likely that the difficulty adjustment for the first few blocks after activation will be limited by PoWMaxAdjustDown. This is not anticipated to cause any problem.</p>
                 <section id="minimum-difficulty-blocks-on-testnet"><h4><span class="section-heading">Minimum difficulty blocks on Testnet</span><span class="section-anchor"> <a rel="bookmark" href="#minimum-difficulty-blocks-on-testnet"><img width="24" height="24" src="assets/images/section-anchor.png" alt=""></a></span></h4>
                     <p>On Testnet from block height 299188 onward, the difficulty adjustment algorithm <a id="id10" class="footnote_reference" href="#protocol-diffadjustment">6</a> allows minimum-difficulty blocks, as described in <a id="id11" class="footnote_reference" href="#zip-0205">10</a>, when the block time is greater than a given threshold. This specification changes this threshold to be proportional to the block target spacing.</p>
-                    <p>That is, if the block time of a block at height <em>height</em> ≥ 299188 is at least 6 · PoWTargetSpacing(<em>height</em>) seconds after that of the preceding block, then the block is a minimum-difficulty block. In that case its <code>nBits</code> field is set to ToCompact(PoWLimit), where PoWLimit is the value defined for Testnet in section 5.3 of the Zcash Protocol Specification <a id="id12" class="footnote_reference" href="#protocol-constants">5</a>, and ToCompact is as defined in section 7.6.4 of that specification <a id="id13" class="footnote_reference" href="#protocol-nbits">7</a>.</p>
+                    <p>That is, if the block time of a block at height <em>height</em> ≥ 299188 is greater than 6 · PoWTargetSpacing(<em>height</em>) seconds after that of the preceding block, then the block is a minimum-difficulty block. In that case its <code>nBits</code> field is set to ToCompact(PoWLimit), where PoWLimit is the value defined for Testnet in section 5.3 of the Zcash Protocol Specification <a id="id12" class="footnote_reference" href="#protocol-constants">5</a>, and ToCompact is as defined in section 7.6.4 of that specification <a id="id13" class="footnote_reference" href="#protocol-nbits">7</a>.</p>
                     <p>Note: a previous revision of this ZIP (and <a id="id14" class="footnote_reference" href="#zip-0205">10</a>) incorrectly said that only the target threshold of minimum-difficulty blocks is affected. In fact the <code>nBits</code> field is as well, and this affects difficulty adjustment for subsequent blocks.</p>
                     <p>This change does not affect Mainnet.</p>
                 </section>

zip-0208.rst

@@ -188,7 +188,7 @@ On Testnet from block height 299188 onward, the difficulty adjustment algorithm
 specification changes this threshold to be proportional to the block target
 spacing.
 
-That is, if the block time of a block at height *height* ≥ 299188 is at least
+That is, if the block time of a block at height *height* ≥ 299188 is greater than
 6 · PoWTargetSpacing(*height*) seconds after that of the preceding block,
 then the block is a minimum-difficulty block. In that case its ``nBits`` field
 is set to ToCompact(PoWLimit), where PoWLimit is the value defined for Testnet