Add end comments for conditional blocks in history entries.

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

protocol/protocol.tex

@@ -10542,14 +10542,14 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
           previously depended on $\abstJ$ being injective.
     \item In $\RedDSA$ verification, clarify that $\RedDSAReprR{}$ used as part of the input to
           $\RedDSAHashToScalar$ must be exactly as encoded in the signature.
-}
+} %sapling
 \canopy{
     \item Specify that \shieldedOutputs of \coinbaseTransactions \MUST use v2 \notePlaintexts after
           \Canopy activation.
     \item Correct a bug in \crossref{saplingdecryptovk}: $\EphemeralPrivate$ is only to be checked
           against $\ToScalar\big(\PRFexpand{\NoteSeedBytes}([4])\kern-0.11em\big)$
           when $\NotePlaintextLeadByte \neq \hexint{01}$.
-}
+} %canopy
 \end{itemize}
 
 
@@ -10564,11 +10564,11 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
           always succeeds, and error handling is more explicit).
     \item Fix a sign error in the fixed-base term of the batch validation equation in
           \crossref{reddsabatchvalidate}.
-}
+} %sapling
 \canopy{
     \item Fix a sign error in the fixed-base term of the batch validation equation in
           \crossref{ed25519batchvalidate}.
-}
+} %canopy
 \end{itemize}
 
 
@@ -10578,18 +10578,18 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
     \item No changes to \Sprout.
 \canopy{
     \item Incorporate changes to \Sapling{} \note encryption from \cite{ZIP-212}.
-}
+} %canopy
     \item Correct an error in the specification of \EdSpecific \validatingKeys:
           they should not have been specified to be checked against $\ExcludedPointEncodings$,
           since libsodium~v1.0.15 does not do so.
 \canopy{
     \item Incorporate \EdSpecific changes for \Canopy from \cite{ZIP-215}.
     \item Add Appendix \crossref{ed25519batchvalidate}.
-}
+} %canopy
     \item Consistently use ``validating'' for signatures and ``verifying'' for proofs.
 \sapling{
     \item Use the symbol $\possqrt{\,\paramdot\,}$ for positive square root.
-}
+} %sapling
 \end{itemize}
 
 
@@ -10598,7 +10598,7 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
 \begin{itemize}
 \sapling{
     \item Reference \cite{ZIP-173} instead of BIP 173.
-}
+} %sapling
     \item Mark more index entries as definitions.
 \end{itemize}
 
@@ -10610,7 +10610,7 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
     \item Network Upgrade 4 has been given the name \Canopy.
 \canopy{
     \item Reference \cite{ZIP-211}, \cite{ZIP-212}, and \cite{ZIP-215} for the \Canopy upgrade.
-}
+} %canopy
     \item Improve LaTeX portability of this specification.
 \end{itemize}
 
@@ -10622,10 +10622,10 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
           in \crossref{joinsplitbalance}.
 \heartwood{
     \item Minor wording clarifications.
-}
+} %heartwood
 \canopy{
     \item Reference \cite{ZIP-251}, \cite{ZIP-207}, and \cite{ZIP-214} for the \Canopy upgrade.
-}
+} %canopy
 \end{itemize}
 
 
@@ -10637,7 +10637,7 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
           The specification has been changed to match the implementation.
 \heartwood{
     \item Add consensus rules for \Heartwood.
-}
+} %heartwood
     \item Remove ``pvc'' \Makefile targets.
     \item Make the \Heartwood specification the default.
     \item Add macros and \Makefile support for building the \Canopy specification.
@@ -10665,7 +10665,7 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
 \sapling{
     \item Use the term \quotedterm{monomorphism} for an injective homomorphism, in
           the context of a \keyMonomorphicSignatureScheme.
-}
+} %sapling
 \end{itemize}
 
 \historyentry{2019.0.9}{2019-12-27}
@@ -10719,7 +10719,7 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
 \blossom{
     \item Note the change to the minimum-difficulty threshold time on the test network
           for \Blossom.
-}
+} %blossom
 \sapling{
     \item Correct the packing of $\nfOld{}$ into input elements in \crossref{cctsaplingspend}.
     \item Add an epigraph from \cite{Carroll1876} to the start of \crossref{jubjub}.
@@ -10739,7 +10739,7 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
     \item Clicking on a section heading now shows section labels.
 \notsprout{
     \item Add a \snarkref{List of Theorems and Lemmata}{theorems}.
-}
+} %notsprout
     \item Changes needed to support TeXLive 2019.
 \end{itemize}