deps: update to bytecount 0.5

bytecount now uses runtime dispatch for enabling SIMD, which means we can
no longer need the avx-accel features. We remove it from ripgrep since the
next release will be a minor version bump, but leave them as no-ops for
the crates that previously used it.

grep/Cargo.toml

@@ -32,6 +32,8 @@ default-features = false
 features = ["suggestions"]
 
 [features]
-avx-accel = ["grep-searcher/avx-accel"]
 simd-accel = ["grep-searcher/simd-accel"]
 pcre2 = ["grep-pcre2"]
+
+# This feature is DEPRECATED. Runtime dispatch is used for SIMD now.
+avx-accel = []