runtime(sh): Update syntax file, command substitution opening paren at EOL

Allow the opening parenthesis of a command substitution to appear at
EOL.

This fixes the issue raised in
https://github.com/vim/vim/issues/17026#issuecomment-2774112284.

closes: #17044

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/syntax/testdir/dumps/sh_13_00.dump b/runtime/syntax/testdir/dumps/sh_13_00.dump
new file mode 100644
index 0000000..7fe0991
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/sh_13_00.dump
@@ -0,0 +1,20 @@
+>#+0#0000e05#ffffff0| |I|s@1|u|e| |#|1|7|0|2|6| |(|b|a|s|h| |h|i|g|h|l|i|g|h|t|i|n|g| |r|e|q|u|i|r|e|s| |s|p|a|c|e| |a|f|t|e|r| |$|(|)@1| +0#0000000&@15
+|#+0#0000e05&| |h|t@1|p|s|:|/@1|g|i|t|h|u|b|.|c|o|m|/|v|i|m|/|v|i|m|/|i|s@1|u|e|s|/|1|7|0|2|6|#|i|s@1|u|e|c|o|m@1|e|n|t|-|2|7@1|4|1@1|2@1|8|4| +0#0000000&@9
+@75
+|_|c|o|m|p|_|c|o|m|p|g|e|n|_|s|p|l|i|t| |-+0#e000e06&|l| +0#0000000&|-+0#e000e06&@1| +0#0000000&|"+0#af5f00255&|$+0#e000e06&|(| +0#0000000&@45
+| +0#e000e06&@3|t|m|u|x| |l|i|s|t|-|c|o|m@1|a|n|d|s| |-|F| |"+0#af5f00255&|#+0#e000002&|{|c|o|m@1|a|n|d|_|l|i|s|t|_|n|a|m|e|}|"+0#af5f00255&| +0#0000000&@26
+| +0#e000e06&@3|t|m|u|x| |l|i|s|t|-|c|o|m@1|a|n|d|s| |-|F| |"+0#af5f00255&|#+0#e000002&|{|c|o|m@1|a|n|d|_|l|i|s|t|_|a|l|i|a|s|}|"+0#af5f00255&| +0#0000000&@25
+|)+0#e000e06&|"+0#af5f00255&| +0#0000000&@72
+@75
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|i+0#0000000&|s|_|b|a|s|h|:| |1|,| @45|1|,|1| @10|A|l@1| 
diff --git a/runtime/syntax/testdir/input/sh_13.sh b/runtime/syntax/testdir/input/sh_13.sh
new file mode 100644
index 0000000..a81c0a4
--- /dev/null
+++ b/runtime/syntax/testdir/input/sh_13.sh
@@ -0,0 +1,8 @@
+# Issue #17026 (bash highlighting requires space after $())
+# https://github.com/vim/vim/issues/17026#issuecomment-2774112284
+
+_comp_compgen_split -l -- "$(
+    tmux list-commands -F "#{command_list_name}"
+    tmux list-commands -F "#{command_list_alias}"
+)"
+