Move annotation classes used for referencing framework Java classes from Skylark into their own package. This allows, e.g., classes in the syntax package to access classes in the cmdline package without creating circular dependencies.

While we're here:

- Removed a couple of unused BUILD deps flagged in [].

- Updated SkylarkRuleImplementationFunctionsTest to remove non-ASCII characters and
  clarify the intent of the test.

--
MOS_MIGRATED_REVID=110360763

src/main/java/com/google/devtools/build/docgen/skylark/SkylarkDoc.java

diff --git a/src/main/java/com/google/devtools/build/docgen/skylark/SkylarkDoc.java b/src/main/java/com/google/devtools/build/docgen/skylark/SkylarkDoc.java
index 941849d..511e474 100644
--- a/src/main/java/com/google/devtools/build/docgen/skylark/SkylarkDoc.java
+++ b/src/main/java/com/google/devtools/build/docgen/skylark/SkylarkDoc.java
@@ -13,15 +13,15 @@
 // limitations under the License.
 package com.google.devtools.build.docgen.skylark;
 
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkSignature;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkSignature.Param;
 import com.google.devtools.build.lib.syntax.EvalUtils;
 import com.google.devtools.build.lib.syntax.FuncallExpression;
 import com.google.devtools.build.lib.syntax.Runtime.NoneType;
 import com.google.devtools.build.lib.syntax.SkylarkList;
 import com.google.devtools.build.lib.syntax.SkylarkList.MutableList;
 import com.google.devtools.build.lib.syntax.SkylarkList.Tuple;
-import com.google.devtools.build.lib.syntax.SkylarkModule;
-import com.google.devtools.build.lib.syntax.SkylarkSignature;
-import com.google.devtools.build.lib.syntax.SkylarkSignature.Param;
 
 import java.util.Arrays;
 import java.util.Map;