docs: fix spelling

Fixes #458

Author: gnikit

docs/editor_integration.rst

@@ -82,7 +82,7 @@ the ``cmd`` option in ``setup{}``
     require'lspconfig'.fortls.setup{
         cmd = {
             'fortls',
-            '--lowercase_intrisics',
+            '--lowercase_intrinsics',
             '--hover_signature',
             '--hover_language=fortran',
             '--use_signature_help'