* Rewrite the real file if history file is a symlink
When the history file is a symbolic link, `fish` used to overwrite
the link with a real file whenever it saved history. This makes
it follow the symlink and overwrite the real file instead.
The same issue was fixed for the `fish_variables` file in 622f2868e
from https://github.com/fish-shell/fish-shell/pull/7728.
This makes `fish_history` behave in the same way. The implementation
is nearly identical.
Since the tests for the two issues are so similar, I combined them
together and slightly expanded the older test.
This also addresses https://github.com/fish-shell/fish-shell/issues/7553.
* Add user-facing error when history renaming fails
Currently, when history file renaming fails, no message is shown to the
user. This happens, for instance, if the history file is a symlink
pointing to another filesystem.
This copies code (with a bit of variation, after reviewer comments) from
589eb34571/src/env_universal_common.cpp (L486-L491)
into `history.cpp`, so that a message is shown to the user.
* fixup! Rewrite the real file if history file is a symlink
