check-code: do not warn on printf \\x or \\[1-9]

When there is a double backslash the following char does not have any special
meaning. So do not warn on this.
Remove the now obsolete no-check-code statement. (It was used wrongly anyway, it
skipped checking the entire file.)

contrib/check-code.py

@@ -68,8 +68,8 b' testpats = ['
     (r'head -c', "don't use 'head -c', use 'dd'"),
     (r'sha1sum', "don't use sha1sum, use $TESTDIR/md5sum.py"),
     (r'ls.*-\w*R', "don't use 'ls -R', use 'find'"),
-    (r'printf.*\\([1-9]|0\d)', "don't use 'printf \NNN', use Python"),
-    (r'printf.*\\x', "don't use printf \\x, use Python"),
+    (r'printf.*[^\\]\\([1-9]|0\d)', "don't use 'printf \NNN', use Python"),
+    (r'printf.*[^\\]\\x', "don't use printf \\x, use Python"),
     (r'\$\(.*\)', "don't use $(expr), use `expr`"),
     (r'rm -rf \*', "don't use naked rm -rf, target a directory"),
     (r'(^|\|\s*)grep (-\w\s+)*[^|]*[(|]\w',

tests/test-subrepo-paths.t

@@ -17,7 +17,7 b' hg debugsub with no remapping'
 hg debugsub with remapping
 
   $ echo '[subpaths]' >> .hg/hgrc
-  $ printf 'http://example.net/lib(.*) = C:\\libs\\\\1-lib\\\n' >> .hg/hgrc # no-check-code
+  $ printf 'http://example.net/lib(.*) = C:\\libs\\\\1-lib\\\n' >> .hg/hgrc
 
   $ hg debugsub
   path sub