aspell: fix -Wdeprecated-declarations for g_module_build_path

```
../../../src/editor/spell.c:177:26: warning: 'g_module_build_path' is deprecated [-Wdeprecated-declarations]
    spell_module_fname = g_module_build_path (NULL, "libaspell");
                         ^
/opt/homebrew/Cellar/glib/2.80.4/include/glib-2.0/gmodule.h:141:1: note: 'g_module_build_path' has been explicitly marked deprecated here
GMODULE_DEPRECATED_IN_2_76
```

Signed-off-by: Yury V. Zaytsev <yury@shurup.com>

src/editor/spell.c

@@ -169,14 +169,10 @@ spell_decode_lang (const char *code)
 static gboolean
 spell_available (void)
 {
-    gchar *spell_module_fname;
-
     if (spell_module != NULL)
         return TRUE;
 
-    spell_module_fname = g_module_build_path (NULL, "libaspell");
-    spell_module = g_module_open (spell_module_fname, G_MODULE_BIND_LAZY);
-    g_free (spell_module_fname);
+    spell_module = g_module_open ("libaspell", G_MODULE_BIND_LAZY);
 
     if (spell_module != NULL
         && ASPELL_FUNCTION_AVAILABLE (new_aspell_config)