Fix command names

Author: dstansby

src/napari_matplotlib/napari.yaml

@@ -3,31 +3,31 @@ display_name: napari-matplotlib
 schema_version: 0.1.0
 contributions:
   commands:
-    - id: napari-matplotlib.histogram
+    - id: napari_matplotlib.histogram
       python_name: napari_matplotlib:HistogramWidget
       title: Make a histogram
 
-    - id: napari-matplotlib.scatter
+    - id: napari_matplotlib.scatter
       python_name: napari_matplotlib:ScatterWidget
       title: Make a scatter plot of image intensities
 
-    - id: napari-matplotlib.features_scatter
+    - id: napari_matplotlib.features_scatter
       python_name: napari_matplotlib:FeaturesScatterWidget
       title: Make a scatter plot of layer features
 
-    - id: napari-matplotlib.slice
+    - id: napari_matplotlib.slice
       python_name: napari_matplotlib:SliceWidget
       title: Plot a 1D slice
 
   widgets:
-    - command: napari-matplotlib.histogram
+    - command: napari_matplotlib.histogram
       display_name: Histogram
 
-    - command: napari-matplotlib.scatter
+    - command: napari_matplotlib.scatter
       display_name: Scatter
 
-    - command: napari-matplotlib.features_scatter
+    - command: napari_matplotlib.features_scatter
       display_name: FeaturesScatter
 
-    - command: napari-matplotlib.slice
+    - command: napari_matplotlib.slice
       display_name: 1D slice