Add comment pull transcripts. Need to update ucm after PRs there are

merged

Author: ChrisPenner

transcripts/share-apis/history-comments/comment-pull.md

@@ -1,4 +1,4 @@
-```ucm:hide
-scratch/main> pull @test/history-comments/main
+```ucm
+scratch/main> pull @transcripts/history-comments/main
 scratch/main> history
 ```

transcripts/share-apis/history-comments/prelude.md

@@ -9,10 +9,11 @@ x = 1
 ```
 
 ```ucm
+scratch/main> update
 scratch/main> config.set author.name Unison 
 scratch/main> history.comment /main: "Initial commit with variable x set to 1"
 scratch/main> alias.term x y
 scratch/main> history.comment /main: "Renamed x to y"
 scratch/main> history
-scratch/main> push @test/history-comments/main
+scratch/main> push @transcripts/history-comments/main
 ```

transcripts/transcript_functions.sh

@@ -11,7 +11,7 @@ mkdir -p "${ucm_xdg_data_dir}/unisonlanguage"
 ucm_credentials_file="${ucm_xdg_data_dir}/unisonlanguage/credentials.json"
 
 # Executable to use when running unison transcripts
-export UCM_PATH="${UCM_PATH:-"$(which ucm)"}"
+export UCM_PATH="$(which unison-history-comment-message)"
 export empty_causal_hash='sg60bvjo91fsoo7pkh9gejbn0qgc95vra87ap6l5d35ri0lkaudl7bs12d71sf3fh6p23teemuor7mk1i9n567m50ibakcghjec5ajg'
 export echo_server_port=9999
 export echo_server="http://localhost:${echo_server_port}"