hopefully fix following google chrome update

TC39 has consensus for trying to deprecate and remove the `assert` keyword in favor of the new `with` keyword in import attribute syntax. That is, `import m from 'foo' assert { type: 'json' }` will now throw a SyntaxError, and developers must change to `import m from 'foo' with { type: 'json' }`. tc39/proposal-import-attributes#135

diagload.js

@@ -1,4 +1,4 @@
-import sample_contexts from "./contexts.json" assert {type: "json"};
+import sample_contexts from "./contexts.json" with {type: "json"};
 
 import {default as createMyModule} from "./latuile-origine.js";
 import {init, mydata, data, resetData, displayCurrent, createMutationObserver} from "./table_edit.js";

table_edit.js

@@ -1,4 +1,4 @@
-import sample_diagdata from "./diagdata.json" assert {type: "json"};
+import sample_diagdata from "./diagdata.json" with {type: "json"};
 
 import {mycontexts, contexts, resetContexts, setContexts, drawDiag, compute_links, ApplyRepartition, enforce_bounding_rectangle, data2contexts} from "./diagload.js";
 import {download} from "./iocomponent.js";