improve error message when test fail because of mismatching string

Author: Techatrix

tests/lsp_features/completion.zig

@@ -4176,10 +4176,10 @@ fn testCompletionWithOptions(
 
             if (actual_doc != null and std.mem.eql(u8, expected_doc, actual_doc.?)) break :doc_blk;
 
-            try error_builder.msgAtIndex("completion item '{s}' should have doc '{s}' but was '{?s}'!", test_uri, cursor_idx, .err, .{
+            try error_builder.msgAtIndex("completion item '{s}' should have doc '{'}' but was '{?'}'!", test_uri, cursor_idx, .err, .{
                 label,
-                expected_doc,
-                actual_doc,
+                std.zig.fmtEscapes(expected_doc),
+                if (actual_doc) |str| std.zig.fmtEscapes(str) else null,
             });
             return error.InvalidCompletionDoc;
         }

tests/lsp_features/hover.zig

@@ -1053,5 +1053,5 @@ fn testHoverWithOptions(
     const markup_context = response.contents.MarkupContent;
 
     try std.testing.expectEqual(options.markup_kind, markup_context.kind);
-    try std.testing.expectEqualStrings(expected, markup_context.value);
+    try zls.testing.expectEqualStrings(expected, markup_context.value);
 }