fix: show the type that failed to plot (#194)

* fix: show the type that failed to plot

Signed-off-by: Henry Schreiner <[email protected]>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Signed-off-by: Henry Schreiner <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: henryiii

src/uproot_browser/plot.py

@@ -42,11 +42,11 @@ def make_hist_title(item: Any, histogram: hist.Hist) -> str:
 
 
 @functools.singledispatch
-def plot(tree: Any) -> None:  # noqa: ARG001
+def plot(tree: Any) -> None:
     """
     Implement this for each type of plottable.
     """
-    msg = "This object is not plottable yet"
+    msg = f"This object ({type(tree)}) is not plottable yet"
     raise RuntimeError(msg)