fix: linux shell inference when spaces or trailing slash in command

[andrewflbarnes]

Fixes #1482 - inferences which fail when the path has a trailing slash or includes a space. Aligns the debug output for windows and unix.

Path with spaces

$ exec -a "/path with space/to/bash" bash

$ pid=$$; while [ -n "$pid" ]; do read pid prog <<< "$(ps -o ppid,comm -p $pid | awk 'NR == 2 {print}')"; echo $pid $prog; done
3634 /path with space/to/bash
1 /Users/xxxxx/Applications/IntelliJ IDEA Ultimate.app/Contents/MacOS/idea
0 /sbin/launchd

$ RUST_LOG=debug cargo run -- env
...
[2025-12-02T22:42:18Z DEBUG fnm::shell::infer::unix] pid 28180 parent process 23954 : target/debug/fnm
[2025-12-02T22:42:18Z DEBUG fnm::shell::infer] binary is not a supported shell: "fnm"
[2025-12-02T22:42:18Z DEBUG fnm::shell::infer::unix] pid 23954 parent process 3634 : /path with space/to/bash
[2025-12-02T22:42:18Z DEBUG fnm::shell::infer::unix] Found supported shell: Bash
export PATH="/Users/xxxxxx/.local/state/fnm_multishells/28180_1764715338497/bin":"$PATH"

Trailing slash on symlink

$ exec /opt/homebrew/bin/bash/

$ pid=$$; while [ -n "$pid" ]; do read pid prog <<< "$(ps -o ppid,comm -p $pid | awk 'NR == 2 {print}')"; echo $pid $prog; done
3634 /opt/homebrew/bin/bash/
1 /Users/xxxxxx/Applications/IntelliJ IDEA Ultimate.app/Contents/MacOS/idea
0 /sbin/launchd

$ RUST_LOG=debug cargo run -- env
...
[2025-12-02T22:50:32Z DEBUG fnm::shell::infer::unix] pid 31244 parent process 23954 : target/debug/fnm
[2025-12-02T22:50:32Z DEBUG fnm::shell::infer] binary is not a supported shell: "fnm"
[2025-12-02T22:50:32Z DEBUG fnm::shell::infer::unix] pid 23954 parent process 3634 : /opt/homebrew/bin/bash/
[2025-12-02T22:50:32Z DEBUG fnm::shell::infer::unix] Found supported shell: Bash
export PATH="/Users/xxxxxx/.local/state/fnm_multishells/31244_1764715832655/bin":"$PATH"

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🦋 Changeset detected

Latest commit: 6574931

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
fnm	Patch

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