Make explicit that (in|ex)clude patterns are for relative

paths and that the leading / is the equivalent of ^ in
regex.

rsync.yo

@@ -651,7 +651,7 @@ useful in combination with a recursive transfer.
 You may use as many --exclude options on the command line as you like
 to build up the list of files to exclude.
 
-See the section on exclude patterns for information on the syntax of 
+See the EXCLUDE PATTERNS section for information on the syntax of 
 this option.
 
 dit(bf(--exclude-from=FILE)) This option is similar to the --exclude
@@ -664,7 +664,7 @@ dit(bf(--include=PATTERN)) This option tells rsync to not exclude the
 specified pattern of filenames. This is useful as it allows you to
 build up quite complex exclude/include rules.
 
-See the section of exclude patterns for information on the syntax of 
+See the EXCLUDE PATTERNS section for information on the syntax of 
 this option.
 
 dit(bf(--include-from=FILE)) This specifies a list of include patterns
@@ -871,6 +871,12 @@ skipped. If it is an include pattern then that filename is not
 skipped. If no matching include/exclude pattern is found then the
 filename is not skipped.
 
+The filenames matched against the exclude/incldue patterns are
+relative to the base directories so patterns should not
+include the path elements to those base directories.  The
+only way in which a pattern will match the absolute path of
+a file or directory is if the base path is the root directory.
+
 Note that when used with -r (which is implied by -a), every subcomponent of
 every path is visited from top down, so include/exclude patterns get
 applied recursively to each subcomponent.
@@ -882,13 +888,17 @@ each. To add multiple patterns use the --include-from and
 The patterns can take several forms. The rules are:
 
 itemize(
+
   it() if the pattern starts with a / then it is matched against the
   start of the filename, otherwise it is matched against the end of
-  the filename.  Thus "/foo" would match a file called "foo" at the base of
-  the tree.  On the other hand, "foo" would match any file called "foo"
+  the filename.
+  This is the equivalent of a leading ^ in regular expressions.
+  Thus "/foo" would match a file called "foo" at the base of the tree.
+  On the other hand, "foo" would match any file called "foo"
   anywhere in the tree because the algorithm is applied recursively from
   top down; it behaves as if each path component gets a turn at being the
   end of the file name.
+  The leading / does not make the pattern an absolute pathname.
 
   it() if the pattern ends with a / then it will only match a
   directory, not a file, link or device.