Fix spelling errors in documentation strings.

Signed-off-by: Mattia Rizzolo <mattia@debian.org>

reprotest/__init__.py

@@ -575,7 +575,7 @@ def cli_parser():
     group1_0.add_argument('--extra-build', metavar='VARIATIONS', default=[], action='append',
         help='Perform another build with the given VARIATIONS (which may be '
         'empty) to be applied on top of what was given for --variations and '
-        '--vary. Each occurence of this flag specifies another build, so e.g. '
+        '--vary. Each occurrence of this flag specifies another build, so e.g. '
         'given twice this will make reprotest perform 4 builds in total.')
     group1_0.add_argument('--auto-build', default=False, action='store_true',
         help='Automatically perform builds to try to determine which specific '

reprotest/mdiffconf.py

@@ -98,7 +98,7 @@ def parse(d, action, one, zero=None, aliases={}):
     obj: The top-level object to apply the action to.
 
     action: The action to apply, specified as a string. The string is split on
-        the leftmost occurence of any supported $operator; everything to the
+        the leftmost occurrence of any supported $operator; everything to the
         left of it is the $attribute and to the right of it is the $operand.
 
         $attribute is in dotted-notation and specifies which $target attribute