yadm-introspect: fix typo in filename (#13939)

pages/common/yadm-introspect.md

@@ -0,0 +1,21 @@
+# yadm-introspect
+
+> Look at data that is managed by `yadm`.
+> The purpose of introspection is to support command line completion.
+> More information: <https://github.com/TheLocehiliosan/yadm/blob/master/yadm.md#commands>.
+
+- Output commands:
+
+`yadm introspect commands`
+
+- Output configs:
+
+`yadm introspect configs`
+
+- Output switches for the main `yadm` command:
+
+`yadm introspect switches`
+
+- Output repo:
+
+`yadm introspect repo`