Bump mvdan/sh from 3.8.0 to 3.9.0 in lib/tools/shellfmt.sh

[github-actions]

Bump mvdan/sh from 3.8.0 to 3.9.0 by bumping SHELLFMT_VERSION in lib/tools/shellfmt.sh.

Release notes

Sourced from mvdan/sh's releases.
Please note that this only shows the release notes for the latest release.

This release drops support for Go 1.21 and includes many fixes.

• cmd/shfmt
  • Switch the diff implementation to remove one dependency
• syntax
  • Protect against overflows in position offset integers
• interp
  • Use os.Pipe for stdin to prevent draining by subprocesses - interp: heredocs get consumed by the first command process executed mvdan/sh#1085
  • Support cancelling reads in builtins when stdin is a file - Cancellable reads; EOF on "read" sets var to "" mvdan/sh#1066
  • Support the nocaseglob bash option - Allow case-insensitive filename globbing; add nocaseglob mvdan/sh#1073
  • Support the Bash 5.2 @k parameter expansion operator
  • Support the test -O and test -G operators on non-Windows - Implement -O and -G tests mvdan/sh#1080
  • Support the read -s builtin flag - interp: add -s support for read builtin mvdan/sh#1063
• expand
  • Add support for case insensitive globbing - Allow case-insensitive filename globbing; add nocaseglob mvdan/sh#1073
  • Don't panic when pattern words are nil - syntax: Parser does not handle unescaped slash as original value in replacement parameter expansion mvdan/sh#1076

A special thanks to @theclapp for their contributors to this release!

Consider becoming a sponsor if you benefit from the work that went into this release!

Binaries built on go version go1.23.0 linux/amd64 with:

CGO_ENABLED=0 go build -trimpath -ldflags="-w -s -X=main.version=v3.9.0"