docs: fix code alignment in example usage (#54)

Author: DenverCoder1

docs/source/usage.rst

@@ -100,21 +100,21 @@ Use a preset style
    +----------+----------+----------+----------+
    """
 
-    output = table2ascii(
-        header=["First", "Second", "Third", "Fourth"],
-        body=[["10", "30", "40", "35"], ["20", "10", "20", "5"]],
-        style=PresetStyle.plain,
-        cell_padding=0,
-        alignments=[Alignment.LEFT] * 4,
-    )
-
-    print(output)
-
-    """
-    First Second Third Fourth
-    10    30     40    35
-    20    10     20    5
-    """
+   output = table2ascii(
+       header=["First", "Second", "Third", "Fourth"],
+       body=[["10", "30", "40", "35"], ["20", "10", "20", "5"]],
+       style=PresetStyle.plain,
+       cell_padding=0,
+       alignments=[Alignment.LEFT] * 4,
+   )
+
+   print(output)
+
+   """
+   First Second Third Fourth
+   10    30     40    35
+   20    10     20    5
+   """
 
 Define a custom style
 ~~~~~~~~~~~~~~~~~~~~~