Revert "Do not use set -e in helper shell scripts"

This reverts commit 0aeb88e663b9b19e173de20b132bef2189c6d7c9.

shell-completion/parse-commands.sh

@@ -1,10 +1,10 @@
 #!/usr/bin/env bash
 # Parse hledger's help and output all commands and command aliases in
 # parenthesis. Do not output single letter command aliases, it's not useful.
-set -uo pipefail
+set -euo pipefail
 
 declare commands_help
-commands_help=$(hledger) || exit
+commands_help=$(hledger)
 {
     sed -rn 's/^\s+([a-z][-a-z]+)\s+.*/\1/p' <<< "$commands_help"
     sed -rn 's/^\s+[a-z][-a-z]+\s+\(([a-z][ ,a-z]+)\).*/\1/p' <<< "$commands_help" |

shell-completion/parse-options.sh

@@ -2,7 +2,7 @@
 # Parse hledger's help and output long options. Do not propose single letter
 # completions. Options requiring an argument make that explicit by appending the
 # equal sign (=)
-set -uo pipefail
+set -euo pipefail
 
 declare subcommand=${1:-}
 declare hledgerArgs=(--help)