bazel syntax: rename ListLiteral to ListExpression

A literal is a value provided in the syntax tree.
By contrast, a list expression involves computation
(of its elements) and may fail.

Also:
- remove enum Kind. A boolean is fine.
- update comments and doc strings.

A follow-up will do the same for DictionaryLiteral.

PiperOrigin-RevId: 269366336
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
index 69de404..0df5a53 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
@@ -1587,7 +1587,7 @@
   }
 
   @Test
-  public void testInvalidAugmentedAssignment_ListLiteral() throws Exception {
+  public void testInvalidAugmentedAssignment_ListExpression() throws Exception {
     new SkylarkTest().testIfErrorContains(
         "cannot perform augmented assignment on a list or tuple expression",
         "def f(a, b):",