Add a `follow_symlinks: bool` option

[jwodder]

InPlace should gain a follow_symlinks: bool option for controlling whether to resolve any symbolic links in the input file path before opening the file for reading. Setting this to True (the default) will result in the same behavior as now. Setting this to False disables symlink resolution.

• Note that this option only controls resolution of symlinks in the name argument; symlinks in the backup argument are never resolved by in-place.
• Note that backup_ext is applied to the input file path after any symlink resolution is performed.

Note to self: Make use of the test cases from the Rust port for this.