fix default-env after latest changes (#10052)

# Description

default env.nu is currently broken after the changes to `str replace`.
This PR should help fix it.

# User-Facing Changes
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crates/nu-utils/src/sample_config/default_env.nu

@@ -13,15 +13,15 @@ def create_left_prompt [] {
     }
 
     let dir = ([
-        ($env.PWD | str substring 0..($home | str length) | str replace --string $home "~"),
+        ($env.PWD | str substring 0..($home | str length) | str replace $home "~"),
         ($env.PWD | str substring ($home | str length)..)
     ] | str join)
 
     let path_color = (if (is-admin) { ansi red_bold } else { ansi green_bold })
     let separator_color = (if (is-admin) { ansi light_red_bold } else { ansi light_green_bold })
     let path_segment = $"($path_color)($dir)"
 
-    $path_segment | str replace --all --string (char path_sep) $"($separator_color)/($path_color)"
+    $path_segment | str replace --all (char path_sep) $"($separator_color)/($path_color)"
 }
 
 def create_right_prompt [] {
@@ -30,8 +30,8 @@ def create_right_prompt [] {
         (ansi reset)
         (ansi magenta)
         (date now | format date '%Y/%m/%d %r')
-    ] | str join | str replace --all "([/:])" $"(ansi green)${1}(ansi magenta)" |
-        str replace --all "([AP]M)" $"(ansi magenta_underline)${1}")
+    ] | str join | str replace --regex --all "([/:])" $"(ansi green)${1}(ansi magenta)" |
+        str replace --regex --all "([AP]M)" $"(ansi magenta_underline)${1}")
 
     let last_exit_code = if ($env.LAST_EXIT_CODE != 0) {([
         (ansi rb)