Project settings: fix semi-linear merge description

Changelog: fixed

app/views/projects/_merge_request_merge_method_settings.html.haml

@@ -19,9 +19,9 @@
       .text-secondary
         = s_('ProjectSettings|Every merge creates a merge commit.')
         %br
-        = s_('ProjectSettings|Fast-forward merges only.')
+        = s_('ProjectSettings|Merging is only allowed when the source branch is up-to-date with its target.')
         %br
-        = s_('ProjectSettings|When there is a merge conflict, the user is given the option to rebase.')
+        = s_('ProjectSettings|When semi-linear merge is not possible, the user is given the option to rebase.')
 
   .form-check.mb-2
     = form.radio_button :merge_method, :ff, class: "js-merge-method-radio form-check-input", data: { qa_selector: 'merge_ff_radio' }

locale/gitlab.pot

@@ -28883,6 +28883,9 @@ msgstr ""
 msgid "ProjectSettings|Merge suggestions"
 msgstr ""
 
+msgid "ProjectSettings|Merging is only allowed when the source branch is up-to-date with its target."
+msgstr ""
+
 msgid "ProjectSettings|No merge commits are created."
 msgstr ""
 
@@ -29054,6 +29057,9 @@ msgstr ""
 msgid "ProjectSettings|When merge request pipelines are enabled in the CI/CD configuration file, pipelines validate the combined results of the source and target branches. %{link_start}How to configure merge request pipelines?%{link_end}"
 msgstr ""
 
+msgid "ProjectSettings|When semi-linear merge is not possible, the user is given the option to rebase."
+msgstr ""
+
 msgid "ProjectSettings|When there is a merge conflict, the user is given the option to rebase."
 msgstr ""