Adds syntax tests, documentation and changelog entry.

Refines comment for array utility function.

test/libsolidity/syntaxTests/array/array_pop.sol

@@ -0,0 +1,7 @@
+contract C {
+    uint[] data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----

test/libsolidity/syntaxTests/array/array_pop_arg.sol

@@ -0,0 +1,8 @@
+contract C {
+    uint[] data;
+    function test() public {
+      data.pop(5);
+    }
+}
+// ----
+// TypeError: (65-76): Wrong argument count for function call: 1 arguments given but expected 0.

test/libsolidity/syntaxTests/array/bytes_pop.sol

@@ -0,0 +1,7 @@
+contract C {
+    bytes data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----

test/libsolidity/syntaxTests/array/dynamic_memory_array_pop.sol

@@ -0,0 +1,8 @@
+contract C {
+    function test() public {
+      uint[] memory data;
+      data.pop();
+    }
+}
+// ----
+// TypeError: (74-82): Member "pop" is not available in uint256[] memory outside of storage.

test/libsolidity/syntaxTests/array/no_array_pop.sol

@@ -0,0 +1,8 @@
+contract C {
+    uint data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----
+// TypeError: (63-71): Member "pop" not found or not visible after argument-dependent lookup in uint256

test/libsolidity/syntaxTests/array/static_storage_array_pop.sol

@@ -0,0 +1,8 @@
+contract C {
+    uint[3] data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----
+// TypeError: (66-74): Member "pop" not found or not visible after argument-dependent lookup in uint256[3] storage ref

test/libsolidity/syntaxTests/array/string_pop.sol

@@ -0,0 +1,8 @@
+contract C {
+    string data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----
+// TypeError: (65-73): Member "pop" not found or not visible after argument-dependent lookup in string storage ref