Fixed typo.

Author: janpgit

docs/cstyle.html

@@ -34,7 +34,7 @@
 
 </p><p>There are a few possible good C styles.  We recommend one that is well
 documented and comes with a Perl script for checking.  The script does not catch
-everything but is good enough.  However, in order to use it propertly, <b>you
+everything but is good enough.  However, in order to use it properly, <b>you
 need to start with following the C style after reading the document below, then
 check the resulting code with the script.</b>  It will not work well if you
 start with non-conforming code and keep fixing the warnings until the script no