Escape backslashes in search and replacement

[lens0021]

Fixes #589.

[Ph0enixKM]

Wow! Tested and this works. Thanks! 🙌

[Mte90]

@lens0021 the tests doesn't work. Can you check what is happening or you need help?

[Mte90]

tests does't work

[lens0021]

@Mte90 Could you give me some hints please? I could not reproduce the failed tests locally.

$ git rev-parse @
946080be7e8c7228d0b448f541b321dbeb4127c8
$ rustc --version
rustc 1.82.0 (f6e511eec 2024-10-15)
$ cargo version
cargo 1.82.0 (8f40fc59f 2024-08-21)
$ rm -rf target
$ cargo build -q
$ cargo test -q

running 223 tests
....................................................................................... 87/223
....................................................................................... 174/223
.................................................
test result: ok. 223 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 2.02s

$ cargo test tests::stdlib::test_stdlib_src_tests_stdlib_replace_regex_ext_ab
    Finished `test` profile [optimized + debuginfo] target(s) in 0.06s
     Running unittests src/main.rs (target/debug/deps/amber-e5eeb9863495dc31)

running 1 test
test tests::stdlib::test_stdlib_src_tests_stdlib_replace_regex_ext_ab ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 222 filtered out; finished in 0.09s

$ cargo test tests::stdlib::test_stdlib_src_tests_stdlib_replace_regex_basic_ab
    Finished `test` profile [optimized + debuginfo] target(s) in 0.05s
     Running unittests src/main.rs (target/debug/deps/amber-e5eeb9863495dc31)

running 1 test
test tests::stdlib::test_stdlib_src_tests_stdlib_replace_regex_basic_ab ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 222 filtered out; finished in 0.06s

$ cargo test tests::stdlib::test_stdlib_src_tests_stdlib_replace_once_ab
    Finished `test` profile [optimized + debuginfo] target(s) in 0.05s
     Running unittests src/main.rs (target/debug/deps/amber-e5eeb9863495dc31)

running 1 test
test tests::stdlib::test_stdlib_src_tests_stdlib_replace_once_ab ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 222 filtered out; finished in 0.05s