cabal-install executable-stripping is off by default, contrary to documentation

[mauke]

Describe the bug
According to https://cabal.readthedocs.io/en/stable/cabal-project-description-file.html#cfg-field-executable-stripping, executable stripping is on by default ("Default value: True"). But it isn't.

To Reproduce

$ mkdir hello-world && cd hello-world
$ cabal init -n
[Info] Guessing dependencies...                                                                                                                                                                                                              
[Info] Using cabal specification: 3.12                                                                                                                                                                                                       
[Warn] unknown license type, you must put a copy in LICENSE yourself.                                                                                                                                                                        
[Info] Creating fresh file CHANGELOG.md...                                                                                                                                                                                                   
[Info] Creating fresh directory ./app...                                                                                                                                                                                                     
[Info] Creating fresh file app/Main.hs...                                                                                                                                                                                                    
[Info] Creating fresh file hello-world.cabal...                                                                                                                                                                                              
[Warn] No synopsis given. You should edit the .cabal file and add one.                                                                                                                                                                       
[Info] You may want to edit the .cabal file and add a Description field.                                                                                                                                                                     

$ cabal install --install-method=copy --installdir=bin
Wrote tarball sdist to
.../hello-world/dist-newstyle/sdist/hello-world-0.1.0.0.tar.gz
Resolving dependencies...
Build profile: -w ghc-9.2.8 -O1
In order, the following will be built (use -v for more details):
 - hello-world-0.1.0.0 (exe:hello-world) (requires build)
Starting     hello-world-0.1.0.0 (exe:hello-world)
Building     hello-world-0.1.0.0 (exe:hello-world)
Installing   hello-world-0.1.0.0 (exe:hello-world)
Completed    hello-world-0.1.0.0 (exe:hello-world)
Copying 'hello-world' to 'bin/hello-world'
$ file bin/hello-world
bin/hello-world: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=f01f23649275f7d42dfb4b6875ba1eaab4558218, with debug_info, not stripped

NB: with debug_info, not stripped

Expected behavior
For comparison:

$ rm bin/hello-world
$ { echo 'packages: .'; echo 'executable-stripping: True'; } > cabal.project
$ cabal install --install-method=copy --installdir=bin
Wrote tarball sdist to
.../hello-world/dist-newstyle/sdist/hello-world-0.1.0.0.tar.gz
Resolving dependencies...
Build profile: -w ghc-9.2.8 -O1
In order, the following will be built (use -v for more details):
 - hello-world-0.1.0.0 (exe:hello-world) (requires build)
Starting     hello-world-0.1.0.0 (exe:hello-world)
Building     hello-world-0.1.0.0 (exe:hello-world)
Installing   hello-world-0.1.0.0 (exe:hello-world)
Completed    hello-world-0.1.0.0 (exe:hello-world)
Copying 'hello-world' to 'bin/hello-world'
$ file bin/hello-world 
bin/hello-world: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=400106adf4c1724d0afd02e49918c9ea835e8dc9, stripped

NB: stripped

This is the result I would have expected without setting executable-stripping manually in the project file.

System information

• Operating system: Ubuntu Linux
• cabal, ghc versions: 3.12.1.0, 9.2.8