BUG: Invalid formatting for shell syntax for closing file descriptors

[titaniumtraveler]

When trying to format shell script containing the bash syntax for closing a file
descriptor, shfmt inserts a space between the variable part and the redirector
part.

Running

echo 'exec {variable_name[1]}<&-' | shfmt -ln=bash --diff

results in

diff <standard input>.orig <standard input>
--- <standard input>.orig
+++ <standard input>
@@ -1,1 +1,1 @@
-exec {variable_name[1]}<&-
+exec {variable_name[1]} <&-

which is invalid bash syntax.

See this sentence from REDIRECTIONS from man bash(1)

If >&- or <&- is preceded by {varname}, the value of varname defines the file descriptor to close.

$ shfmt --version
v3.10.0