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 !1408 with adinapoli/issue-16874 in 319 minutes and 46 seconds (queued for 1 second)
latest detached
Status Job ID Name Coverage
  Lint
passed #124149
lint
ghc-linters

00:01:06

passed #124150
lint
lint-linters

00:01:10

passed #124153
lint
lint-submods-mr

00:00:14

passed #124151
lint
lint-testsuite

00:00:15

passed #124152
lint
typecheck-testsuite

00:00:14

 
  Build
passed #124155
x86_64-linux
hadrian-ghc-in-ghci

00:14:48

passed #124157
x86_64-linux
release-x86_64-linux-deb9-dwarf

01:54:30

passed #124156
x86_64-linux
validate-x86_64-linux-deb9-debug

01:55:36

passed #124154
x86_64-linux
validate-x86_64-linux-deb9-hadrian

01:59:32

 
  Full Build
failed #124159
aarch64-linux allowed to fail
validate-aarch64-linux-deb9

02:59:11

passed #124160
x86_64-linux
validate-i386-linux-deb9

01:03:38

passed #124158
x86_64-darwin
validate-x86_64-darwin

01:29:17

passed #124161
x86_64-linux
validate-x86_64-linux-deb9-integer-simple

01:00:49

passed #124162
x86_64-linux
validate-x86_64-linux-deb9-unreg

02:01:48

passed #124163
x86_64-linux
validate-x86_64-linux-fedora27

01:07:13

failed #124165
x86_64-windows allowed to fail
validate-x86_64-windows

02:23:37

failed #124164
x86_64-windows allowed to fail
validate-x86_64-windows-hadrian

00:28:42

 
  Cleanup
passed #124166
x86_64-darwin
cleanup-darwin

00:00:05

 
  Packaging
passed #124167
x86_64-linux
doc-tarball

00:03:55

 
  Testing
manual #124168
x86_64-linux allowed to fail manual
hackage
passed #124169
x86_64-linux
perf-nofib

00:15:21

 
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=124159 responseStatus=201 Created token=ey912a8R
Uploading artifacts...
junit.xml: found 1 matching files

Uploading artifacts to coordinator... ok
id=124159 responseStatus=201 Created token=ey912a8R
ERROR: Job failed: exit code 1
failed
validate-x86_64-windows-hadrian Full Build
   Speed :            22434230 Bytes/sec.
Speed : 1283.696 MegaBytes/min.
Ended : Monday, July 15, 2019 8:54:34 AM

Uploading artifacts...
Runtime platform arch=amd64 os=windows pid=4768 revision=1f513601 version=11.10.1
WARNING: ghc.tar.xz: no matching files
ERROR: No files to upload
ERROR: Job failed: exit status 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=124165 responseStatus=201 Created token=Dsoos-gq
Uploading artifacts...
Runtime platform
arch=amd64 os=windows pid=4704 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=124165 responseStatus=201 Created token=Dsoos-gq
ERROR: Job failed: exit status 2