std: Fix typo in getopts doc attribute

Author: bkircher

src/libstd/getopts.rs

@@ -4,12 +4,12 @@ Simple getopt alternative.
 Construct a vector of options, either by using reqopt, optopt, and optflag or
 by building them from components yourself, and pass them to getopts, along
 with a vector of actual arguments (not including argv[0]). You'll either get a
-failure code back, or a match.  You'll have to verify whether the amount of
+failure code back, or a match. You'll have to verify whether the amount of
 'free' arguments in the match is what you expect. Use opt_* accessors to get
 argument values out of the match object.
 
 Single-character options are expected to appear on the command line with a
-single preceeding dash; multiple-character options are expected to be
+single preceding dash; multiple-character options are expected to be
 proceeded by two dashes. Options that expect an argument accept their argument
 following either a space or an equals sign.