hotfix issue with path join

Not sure why I didn't test these changes, but the path-join function
didn't actually work fully as expected.
Now, various edge cases have been ironed out:
"/path" + "/foo/bar" -> "/foo/bar", instead of "/path/foo/bar"
"" + "code.fnl" -> "code.fnl", instead of "/code.fnl"

src/fennel-ls/utils.fnl

@@ -198,15 +198,14 @@ WARNING: this is only used in the test code, not in the real language server"
     (= (path:sub 1 1) "/")))
 
 (λ path-join [path suffix]
-  (-> (.. path path-sep suffix)
-    ;; delete duplicate
-    ;; windows
-    (: :gsub "^%.\\" "")
-    (: :gsub "\\+" "\\")
-    ;; modern society
-    (: :gsub "^%./" "")
-    (: :gsub "/+" "/")
-    (->> (pick-values 1))))
+  (if (absolute-path? suffix) suffix
+      (= path "") suffix
+      (let [clean-path (path:gsub "[\\/]?$" path-sep) ; ensure trailing slash
+            clean-suffix (if (or (= (suffix:sub 1 2) "./")
+                                 (= (suffix:sub 1 2) ".\\"))
+                             (suffix:sub 3)
+                             suffix)]
+        (.. clean-path clean-suffix))))
 
 (fn find [t x ?k]
   (match (next t ?k) (k x) k (k y_) (find t x k)))

test/misc.fnl

@@ -43,6 +43,28 @@
   (create-client "(let [map {}] (set (. map (tostring :a)) :b))")
   nil)
 
+(fn test-path-join []
+  ;; Basic path joining
+  (faith.= "path/file" (utils.path-join "path/" "file"))
+  (faith.= "path/file" (utils.path-join "path" "file"))
+  (faith.= "path/file" (utils.path-join "path" "./file"))
+
+  ; Empty path - return suffix as-is
+  (faith.= "file" (utils.path-join "" "file"))
+  (faith.= "main.fnl" (utils.path-join "" "main.fnl"))
+  (faith.= "path/" (utils.path-join "path" ""))
+
+  ; Absolute suffix should override base path
+  (faith.= "/usr/share/awesome/lib" (utils.path-join "/home/myusername/.config/awesome/" "/usr/share/awesome/lib"))
+
+  ; Leading ./ in suffix should be stripped
+  (faith.= "/home/myusername/my-project/main.fnl" (utils.path-join "/home/myusername/my-project" "./main.fnl"))
+
+  ; Nested relative paths
+  (faith.= "a/b/c/d" (utils.path-join "a/b" "c/d"))
+  nil)
+
 {: test-multi-sym-split
  : test-find-symbol
- : test-failure}
+ : test-failure
+ : test-path-join}