Replace purescript-trim with string-trim

This is a common helper Emacs had for a while, no need to keep our own
function.

Author: Hi-Angel

purescript-indent.el

@@ -91,6 +91,9 @@
 (require 'purescript-vars)
 (require 'purescript-string)
 (require 'cl-lib)
+(eval-when-compile
+  (when (< emacs-major-version 28)
+    (require 'subr-x)))
 
 (defgroup purescript-indent nil
   "PureScript indentation."
@@ -655,8 +658,8 @@ symbols in the sexp."
           (string-match "where[ \t]*" purescript-indent-current-line-first-ident))
          (diff-first                 ; not a function def with the same name
           (or (null valname-string)
-              (not (string= (purescript-trim valname-string)
-                            (purescript-trim purescript-indent-current-line-first-ident)))))
+              (not (string= (string-trim valname-string)
+                            (string-trim purescript-indent-current-line-first-ident)))))
 
          ;; (is-type-def
          ;;  (and rpurs-sign (eq (char-after rpurs-sign) ?\:)))

purescript-mode.el

@@ -439,7 +439,7 @@ Brings up the documentation for purescript-mode-hook."
       (message "%s"
                (concat (car lines)
                        (if (and (cdr lines) (stringp (cadr lines)))
-                           (format " [ %s .. ]" (purescript-string-take (purescript-trim (cadr lines)) 10))
+                           (format " [ %s .. ]" (purescript-string-take (string-trim (cadr lines)) 10))
                          ""))))))
 
 (defun purescript-current-line-string ()

purescript-string.el

@@ -1,12 +1,4 @@
 ;;; purescript-string.el --- string manipulation utilties -*- lexical-binding: t -*-
-;;;###autoload
-(defun purescript-trim (string)
-  (replace-regexp-in-string
-   "^[ \t\n]+" ""
-   (replace-regexp-in-string
-    "[ \t\n]+$" ""
-    string)))
-
 ;;;###autoload
 (defun purescript-string-take (string n)
   "Take n chars from string."