fix: add missing space between two words (#12781)

Otherwise, logs show such lines:
HINT: Ensure that MainMenu uses `panels` instead of `content_panels`or set up an `edit_handler` ...

CHANGELOG.txt

@@ -53,6 +53,7 @@ Changelog
  * Fix: Reduce confusing spacing below StreamField blocks help text (Rishabh Sharma)
  * Fix: Prevent redundant calls to `Site.find_for_request()` from `Page.get_url_parts()` (Andy Babic)
  * Fix: Prevent error on listings when searching and filtering by locale (Matt Westcott, Sage Abdullah)
+ * Fix: Add missing space in panels check warning message (Stéphane Blondon)
  * Docs: Move the model reference page from reference/pages to the references section as it covers all Wagtail core models (Srishti Jaiswal)
  * Docs: Move the panels reference page from references/pages to the references section as panels are available for any model editing, merge panels API into this page (Srishti Jaiswal)
  * Docs: Move the tags documentation to standalone advanced topic, instead of being inside the reference/pages section (Srishti Jaiswal)

CONTRIBUTORS.md

@@ -867,6 +867,7 @@
 * Joren Hammudoglu
 * Rishabh Sharma
 * Mike Gifford
+* Stéphane Blondon
 
 ## Translators
 

docs/releases/6.4.md

@@ -66,6 +66,7 @@ depth: 1
  * Reduce confusing spacing below StreamField blocks help text (Rishabh Sharma)
  * Prevent redundant calls to `Site.find_for_request()` from `Page.get_url_parts()` (Andy Babic)
  * Prevent error on listings when searching and filtering by locale (Matt Westcott, Sage Abdullah)
+ * Add missing space in panels check warning message (Stéphane Blondon)
 
 ### Documentation
 

wagtail/admin/checks.py

@@ -152,7 +152,7 @@ There are no tabs on non-Page model editing within InlinePanels.""".format(
                 class_name, panel_name
             )
         else:
-            error_hint = """Ensure that {} uses `panels` instead of `{}`\
+            error_hint = """Ensure that {} uses `panels` instead of `{}` \
 or set up an `edit_handler` if you want a tabbed editing interface.
 There are no default tabs on non-Page models so there will be no \
 {} tab for the {} to render in.""".format(

wagtail/snippets/tests/test_snippets.py

@@ -6041,7 +6041,7 @@ class TestPanelConfigurationChecks(WagtailTestUtils, TestCase):
 
         warning = checks.Warning(
             "StandardSnippet.content_panels will have no effect on snippets editing",
-            hint="""Ensure that StandardSnippet uses `panels` instead of `content_panels`\
+            hint="""Ensure that StandardSnippet uses `panels` instead of `content_panels` \
 or set up an `edit_handler` if you want a tabbed editing interface.
 There are no default tabs on non-Page models so there will be no\
  Content tab for the content_panels to render in.""",