fix: 🐛 handle windows Path casing (#9210)

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PATH and Path are different (in nushell at least) based on the OS

# User-Facing Changes
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None the command now works as expected

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crates/nu-std/lib/mod.nu

@@ -38,14 +38,17 @@ export def-env "path add" [
     --append (-a)  # append to $env.PATH instead of prepending to.
     ...paths  # the paths to add to $env.PATH.
 ] {
-    let-env PATH = (
-        $env.PATH
-        | if $append { append $paths }
-        else { prepend $paths }
+    let path_name = if "PATH" in $env { "PATH" } else { "Path" }
+
+    let-env $path_name = (
+            $env
+            | get $path_name
+            | if $append { append $paths }
+            else { prepend $paths }
     )
     
     if $ret {
-        $env.PATH
+        $env | get $path_name
     }
 }
 

crates/nu-std/tests/test_std.nu

@@ -3,23 +3,27 @@ use std
 export def test_path_add [] {
     use std "assert equal"
 
-    with-env [PATH []] {
-        assert equal $env.PATH []
+    let path_name = if "PATH" in $env { "PATH" } else { "Path" }
+
+    with-env [$path_name []] {
+        def get_path [] { $env | get $path_name }
+    
+        assert equal (get_path) []
 
         std path add "/foo/"
-        assert equal $env.PATH ["/foo/"]
+        assert equal (get_path) ["/foo/"]
 
         std path add "/bar/" "/baz/"
-        assert equal $env.PATH ["/bar/", "/baz/", "/foo/"]
+        assert equal (get_path) ["/bar/", "/baz/", "/foo/"]
 
-        let-env PATH = []
+        let-env $path_name = []
 
         std path add "foo"
         std path add "bar" "baz" --append
-        assert equal $env.PATH ["foo", "bar", "baz"]
+        assert equal (get_path) ["foo", "bar", "baz"]
 
         assert equal (std path add "fooooo" --ret) ["fooooo", "foo", "bar", "baz"]
-        assert equal $env.PATH ["fooooo", "foo", "bar", "baz"]
+        assert equal (get_path) ["fooooo", "foo", "bar", "baz"]
     }
 }