Bash integration: Handle existing PROMPT_COMMAND ending with a literal newline

docs/changelog.rst

@@ -53,6 +53,8 @@ Detailed list of changes
 
 - Bash integration: Prevent shell integration code from running twice if user enables both automatic and manual integration
 
+- Bash integration: Handle existing PROMPT_COMMAND ending with a literal newline
+
 - Fix continued lines not having their continued status reset on line feed (:iss:`4837`)
 
 - macOS: Allow the New kitty Tab/Window Here services to open multiple selected folders.  (:pull:`4848`)

shell-integration/bash/kitty.bash

@@ -251,7 +251,7 @@ _ksi_main() {
     elif [[ $(builtin declare -p PROMPT_COMMAND 2> /dev/null) =~ 'declare -a PROMPT_COMMAND' ]]; then
         PROMPT_COMMAND+=("$pc")
     else
-        PROMPT_COMMAND="${PROMPT_COMMAND%% }"
+        PROMPT_COMMAND="${PROMPT_COMMAND%%[[:space:]]}"
         PROMPT_COMMAND="${PROMPT_COMMAND%%;}"
         PROMPT_COMMAND+="; $pc"
     fi