Line wrap when pp long expressions (fixes #16874)

This commit fixes #16874 by using `fsep` rather than `sep` when pretty
printing long patterns and expressions.
21 jobs for master in 330 minutes and 44 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Lint
passed #127766
lint
lint-linters

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passed #127769
lint
lint-submods-branch

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lint
lint-testsuite

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lint
typecheck-testsuite

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  Build
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x86_64-linux
hadrian-ghc-in-ghci

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x86_64-linux
release-x86_64-linux-deb9-dwarf

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x86_64-linux
validate-x86_64-linux-deb9-debug

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x86_64-linux
validate-x86_64-linux-deb9-hadrian

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  Full Build
failed #127775
aarch64-linux allowed to fail
validate-aarch64-linux-deb9

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passed #127776
x86_64-linux
validate-i386-linux-deb9

01:31:16

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x86_64-darwin
validate-x86_64-darwin

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failed #127777
x86_64-linux
validate-x86_64-linux-deb9-integer-simple

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x86_64-linux
validate-x86_64-linux-deb9-unreg

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x86_64-linux
validate-x86_64-linux-fedora27

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failed #127781
x86_64-windows allowed to fail
validate-x86_64-windows

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x86_64-windows
validate-x86_64-windows-hadrian

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  Cleanup
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cleanup-darwin

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  Packaging
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doc-tarball
 
  Testing
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hackage
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  Deploy
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x86_64-linux allowed to fail
pages
 
Name Stage Failure
failed
validate-aarch64-linux-deb9 Full Build
$ cp -Rf $HOME/.cabal cabal-cache
Uploading artifacts...
ghc-*.tar.xz: found 1 matching files
junit.xml: found 1 matching files

Uploading artifacts to coordinator... ok
id=127775 responseStatus=201 Created token=rAAtVT2D
Uploading artifacts...
junit.xml: found 1 matching files

Uploading artifacts to coordinator... ok
id=127775 responseStatus=201 Created token=rAAtVT2D
ERROR: Job failed: exit code 1
failed
validate-x86_64-windows Full Build
junit.xml: found 1 matching files                  
WARNING: Failed to load system CertPool:crypto/x509: system root pool is not available on Windows
Uploading artifacts to coordinator... ok
id=127781 responseStatus=201 Created token=g8js9ine
Uploading artifacts...
Runtime platform
arch=amd64 os=windows pid=3888 revision=1f513601 version=11.10.1
junit.xml: found 1 matching files

WARNING: Failed to load system CertPool:crypto/x509: system root pool is not available on Windows
Uploading artifacts to coordinator... ok
id=127781 responseStatus=201 Created token=g8js9ine
ERROR: Job failed: exit status 2
failed
validate-x86_64-linux-deb9-integer-simple Full Build There has been a runner system failure, please try again
Identity added: /home/ghc/.ssh/perf_rsa (/home/ghc/.ssh/perf_rsa)
Warning: Permanently added the ED25519 host key for IP address '147.75.105.105' to the list of known hosts.
From gitlab.haskell.org:ghc/ghc-performance-notes
94dbfa909e..db68ccfc4d refs/notes/perf -> refs/notes/perf
git notes --ref=perf append -F /tmp/tmp.f4QvCXrJD4 HEAD
git push git@gitlab.haskell.org:ghc/ghc-performance-notes.git refs/notes/perf
To gitlab.haskell.org:ghc/ghc-performance-notes.git
db68ccfc4d..109f3f1d79 refs/notes/perf -> refs/notes/perf
ERROR: Job failed (system failure): Error: No such container: 5dbfe481fa2c730fcf1dc4ae55df6eed7f3c8874d1d67ffb26780baf4c9ab1a7 (executor_docker.go:975:0s)