undeprecate info

Deprecation/removal was overzealous.

Closes  #13407

IPython/core/oinspect.py

@@ -588,7 +588,7 b' class Inspector(Colorable):'
             Titles or keys to omit from output (can be set, tuple, etc., anything supporting `in`)
         """
 
-        info = self._info(obj, oname=oname, info=info, detail_level=detail_level)
+        info = self.info(obj, oname=oname, info=info, detail_level=detail_level)
 
         _mime = {
             'text/plain': [],
@@ -702,15 +702,22 b' class Inspector(Colorable):'
             del info['text/html']
         page.page(info)
 
-    def info(self, obj, oname="", formatter=None, info=None, detail_level=0):
-        """DEPRECATED since 5.0. Compute a dict with detailed information about an object."""
-        if formatter is not None:
-            warnings.warn('The `formatter` keyword argument to `Inspector.info`'
-                     'is deprecated as of IPython 5.0 and will have no effects.',
-                      DeprecationWarning, stacklevel=2)
-        return self._info(obj, oname=oname, info=info, detail_level=detail_level)
+    def _info(self, obj, oname="", info=None, detail_level=0):
+        """
+        Inspector.info() was likely unproperly marked as deprecated
+        while only a parameter was deprecated. We "un-deprecate" it.
+        """
+
+        warnings.warn(
+            "The `Inspector.info()` has been un-deprecated as of 8.0 and the"
+            " `formatter=` keyword removed. `Inspector._info` is now an alias."
+            " You can always call `.info()` directly.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        return self.info(obj, oname=oname, info=info, detail_level=detail_level)
 
-    def _info(self, obj, oname='', info=None, detail_level=0) -> dict:
+    def info(self, obj, oname="", info=None, detail_level=0) -> dict:
         """Compute a dict with detailed information about an object.
 
         Parameters