[docs][llvm-dwarfdump] Make the --show-parents and --show-children help text and docs more consistent and correct

[jhenderson]

Summary

The docs and help text for --show-parents and --show-children were a bit inconsistent. The help text claimed they had an effect when "=<offset>" was used, whereas the doc said it had an effect when "--find" or "--name" were used. This change changes the doc to mention "=<offset>" and removes this reference from the help text, to avoid having a very long description in the help text (it still says "when selectively printing entries").

[JDevlieghere]

Thanks!

llvm/trunk/docs/CommandGuide/llvm-dwarfdump.rst

.. option:: --arch=<arch>
             Dump DWARF debug information for the specified CPU architecture.
             Architectures may be specified by name or by number.  This
             option can be specified multiple times, once for each desired
             architecture.  All CPU architectures will be printed by
             default.
 
 .. option:: -c, --show-children
 
-            Show a debug info entry's children when using
-            the :option:`--debug-info`, :option:`--find`,
-            and :option:`--name` options.
+            Show a debug info entry's children when selectively printing with
+            the `=<offset>` argument of :option:`--debug-info`, or options such
+            as :option:`--find` or :option:`--name`.
 
 .. option:: --color
 
             Use colors in output.
 
 .. option:: -f <name>, --find=<name>
 
             Search for the exact text <name> in the accelerator tables

 
 .. option:: -o <path>
 
             Redirect output to a file specified by <path>, where `-` is the
             standard output stream.
 
 .. option:: -p, --show-parents
 
-            Show a debug info entry's parent objects when using the
-            :option:`--debug-info`, :option:`--find`, and
-            :option:`--name` options.
+            Show a debug info entry's parents when selectively printing with
+            the `=<offset>` argument of :option:`--debug-info`, or options such
+            as :option:`--find` or :option:`--name`.
 
 .. option:: --parent-recurse-depth=<N>
 
             Only recurse to a maximum depth of <N> when displaying parents of
             debug info entries.
 
 .. option:: --quiet
 

llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp

static opt<bool>
     UseRegex("regex",
              desc("Treat any <pattern> strings as regular expressions when "
                   "searching instead of just as an exact string match."),
              cat(DwarfDumpCategory));
 static alias RegexAlias("x", desc("Alias for -regex"), aliasopt(UseRegex));
 static opt<bool>
     ShowChildren("show-children",
                  desc("Show a debug info entry's children when selectively "
-                      "printing with the =<offset> option."),
+                      "printing entries."),
                  cat(DwarfDumpCategory));
 static alias ShowChildrenAlias("c", desc("Alias for -show-children."),
                                aliasopt(ShowChildren));
 static opt<bool>
     ShowParents("show-parents",
                 desc("Show a debug info entry's parents when selectively "
-                     "printing with the =<offset> option."),
+                     "printing entries."),
                 cat(DwarfDumpCategory));
 static alias ShowParentsAlias("p", desc("Alias for -show-parents."),
                               aliasopt(ShowParents));
 static opt<bool>
     ShowForm("show-form",
              desc("Show DWARF form types after the DWARF attribute types."),
              cat(DwarfDumpCategory));
 static alias ShowFormAlias("F", desc("Alias for -show-form."),