Fixing extra commas.

While the file was never strict JSON, it really should be as close as
possible.

example_metadata.py

@@ -7,26 +7,26 @@
         "core:datatype": "cf32_le",         # The datatype of the recording (here, little-endian complex 32-bit float)
         "core:sample_rate": 10000000,       # The sample rate of the recording (10 MHz, here).
         "core:version": "0.0.1",            # Version of the SigMF spec used.
-        "core:description": "An example metadafile for a SigMF recording.",
+        "core:description": "An example metadafile for a SigMF recording."
     },
     "captures": [
         # The `captures` array contains capture segment objects, sorted by the `sample_start` value
         {
             "core:sample_start": 0,         # The sample index that these parameters take effect.
             "core:frequency": 900000000,    # The center frequency of the recording (900 MHz, here).
-            "core:time": "2017-02-01T11:33:17053240428Z",
+            "core:time": "2017-02-01T11:33:17053240428Z"
         },
         {
             "core:sample_start": 100000,    # Mandatory
-            "core:frequency": 950000000,    # Now at 950 MHz
-        },
+            "core:frequency": 950000000     # Now at 950 MHz
+        }
     ],
     "annotations": [
         # The `annotations` array contains annotation segment objects, sorted by the `sample_start` value
         {
             "core:sample_start": 1000000,   # The sample index at which this annotation first applies.
             "core:sample_count": 120000,    # The number of samples that this annotation applies to.
-            "core:comment": "Some text comment about stuff happening",
-        },
-    ],
+            "core:comment": "Some text comment about stuff happening"
+        }
+    ]
 }