Fix .cache-ignore and document it

- Before this changes '.cache-ignore' worked the other way around (as a
  whitelist)

References:

README.md

@@ -118,6 +118,12 @@ $cache.freeze;
     -  Old  
     A source name that is in the cache but no longer reflects an existing source.
 
+    - **.cache-ignore**: You can create a file named `.cache-ignore` containing Perl 6 regular expressions. Pod6 filenames in `$source` matching at least one of the provided regexes, will be ignored.
+
+    Example:
+    ~~~
+    *podignored*.pod6
+    ~~~
 ## LICENSE
 
 You can use and distribute this module under the terms of the The Artistic License 2.0. See the LICENSE file included in this distribution for complete details.

lib/Pod/To/Cached.pm6

@@ -202,7 +202,7 @@ method filter-pods(:@pods) {
     if (IGNORE_FILE.IO.e) {
         my @regexs = IGNORE_FILE.IO.slurp.split("\n", :skip-empty);
         my @filtered = @pods;
-        for @regexs -> $regex { @filtered .= grep(/<{$regex}>/); }
+        for @regexs -> $regex { @filtered .= grep({not /<{$regex}>/}); }
         return @filtered;
     }
     return @pods;

t/060-cache-ignore.t

@@ -19,25 +19,25 @@ create-pods("test2.pod6");
 
 #--MARKER-- Test 1
 $cache .= new( :source( DOC ), :path( REP ), :verbose);
-is-deeply $cache.get-pods, 
-          ["t/tmp/doc-ignore/test2.pod6",
-           "t/tmp/doc-ignore/test1.pod6"],
+is-deeply $cache.get-pods.sort, 
+          ("t/tmp/doc-ignore/test1.pod6",
+           "t/tmp/doc-ignore/test2.pod6"),
           IGNORE_FILE ~ " does not exist";
 
 #--MARKER-- Test 2
 IGNORE_FILE.IO.spurt("");
 $cache .= new( :source( DOC ), :path( REP ), :verbose);
-is-deeply $cache.get-pods, 
-          ["t/tmp/doc-ignore/test2.pod6",
-           "t/tmp/doc-ignore/test1.pod6"],
+is-deeply $cache.get-pods.sort,
+          ("t/tmp/doc-ignore/test1.pod6",
+           "t/tmp/doc-ignore/test2.pod6"),
           IGNORE_FILE ~ " is empty";
 unlink IGNORE_FILE;
 
 #--MARKER-- Test 3
 IGNORE_FILE.IO.spurt("test2");
 $cache .= new( :source( DOC ), :path( REP ), :verbose);
-is-deeply $cache.get-pods, 
-          ["t/tmp/doc-ignore/test2.pod6"],
+is-deeply $cache.get-pods.sort, 
+          ("t/tmp/doc-ignore/test1.pod6",),
           IGNORE_FILE ~ " with simple regex";
 unlink IGNORE_FILE;