Remove dartdoc.

sdk/lib/_internal/dartdoc/README.txt

Index: sdk/lib/_internal/dartdoc/README.txt
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--- sdk/lib/_internal/dartdoc/README.txt	(revision 32349)
+++ sdk/lib/_internal/dartdoc/README.txt	(working copy)
@@ -1,84 +0,0 @@
-Dartdoc generates static HTML documentation from Dart code.
-
-To use it, from this directory, run:
-
-    $ dartdoc <path to .dart file>
-
-This will create a "docs" directory with the docs for your libraries.
-
-
-How docs are generated
-----------------------
-
-To make beautiful docs from your library, dartdoc parses it and every library it
-imports (recursively). From each library, it parses all classes and members,
-finds the associated doc comments and builds crosslinked docs from them.
-
-"Doc comments" can be in one of a few forms:
-
-    /**
-     * JavaDoc style block comments.
-     */
-
-    /** Which can also be single line. */
-
-    /// Triple-slash line comments.
-    /// Which can be multiple lines.
-
-The body of a doc comment will be parsed as markdown which means you can apply
-most of the formatting and structuring you want while still having docs that
-look nice in plain text. For example:
-
-    /// This is a doc comment. This is the first paragraph in the comment. It
-    /// can span multiple lines.
-    ///
-    /// A blank line starts a new paragraph like this one.
-    ///
-    /// *   Unordered lists start with `*` or `-` or `+`.
-    /// *   And can have multiple items.
-    ///     1. You can nest lists.
-    ///     2. Like this numbered one.
-    ///
-    /// ---
-    ///
-    /// Three dashes, underscores, or tildes on a line by themselves create a
-    /// horizontal rule.
-    ///
-    ///     to.get(a.block + of.code) {
-    ///       indent(it, 4.spaces);
-    ///       like(this);
-    ///     }
-    ///
-    /// There are a few inline styles you can apply: *emphasis*, **strong**,
-    /// and `inline code`. You can also use underscores for _emphasis_ and
-    /// __strong__.
-    ///
-    /// An H1 header using equals on the next line
-    /// ==========================================
-    ///
-    /// And an H2 in that style using hyphens
-    /// -------------------------------------
-    ///
-    /// # Or an H1 - H6 using leading hashes
-    /// ## H2
-    /// ### H3
-    /// #### H4 you can also have hashes at then end: ###
-    /// ##### H5
-    /// ###### H6
-
-There is also an extension to markdown specific to dartdoc: A name inside
-square brackets that is not a markdown link (i.e. doesn't have square brackets
-or parentheses following it) like:
-
-    Calls [someMethod], passing in [arg].
-
-is understood to be the name of some member or type that's in the scope of the
-member where that comment appears. Dartdoc will automatically figure out what
-the name refers to and generate an approriate link to that member or type.
-
-
-Attribution
------------
-
-dartdoc uses the delightful Silk icon set by Mark James.
-http://www.famfamfam.com/lab/icons/silk/