bump rust version to 1.79.0 (#13809)

# Description

This PR bumps our rust version from 1.78 to 1.79.0 due to the 1.81.0
release.

# User-Facing Changes
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crates/nu-system/src/windows.rs

@@ -992,7 +992,7 @@ fn get_name(psid: PSID) -> Option<(String, String)> {
 fn from_wide_ptr(ptr: *const u16) -> String {
     unsafe {
         assert!(!ptr.is_null());
-        let len = (0..std::isize::MAX)
+        let len = (0..isize::MAX)
             .position(|i| *ptr.offset(i) == 0)
             .unwrap_or_default();
         let slice = std::slice::from_raw_parts(ptr, len);