typeahead: Replace code block language hint text with more clear options

This commit
- Replace the blank option with an italicized option that's the current
   default language, if there is one selected with "default" label.
- Make the "text" option more informative by adding (no highlighting)
   to the label.
- Remove the hint for "text".
- Prioritize as left to right, before start typing:
   blank/default language, text, quote, spoiler, math, everything else...

fixes: #33682

web/tests/composebox_typeahead.test.cjs

@@ -2306,7 +2306,10 @@ test("content_highlighter_html", ({override_rewire}) => {
     ct.get_or_set_completing_for_tests("syntax");
     th_render_typeahead_item_called = false;
     override_rewire(typeahead_helper, "render_typeahead_item", (item) => {
-        assert.deepEqual(item, {primary: "py"});
+        assert.deepEqual(item, {
+            is_default_language: false,
+            primary: "py",
+        });
         th_render_typeahead_item_called = true;
     });
     ct.content_highlighter_html({type: "syntax", language: "py"});

web/tests/realm_playground.test.cjs

@@ -78,6 +78,10 @@ run_test("get_pygments_typeahead_list_for_settings", () => {
     let iterator = candidates.entries();
     assert.equal(iterator.next().value[1], $t({defaultMessage: "Custom language: custom_lang"}));
     assert.equal(iterator.next().value[1], $t({defaultMessage: "Custom language: invent_a_lang"}));
+    assert.equal(iterator.next().value[1], "Text only (text, text)");
+    assert.equal(iterator.next().value[1], "quote (quote, quote)");
+    assert.equal(iterator.next().value[1], "spoiler (spoiler, spoiler)");
+    assert.equal(iterator.next().value[1], "math (math, math)");
     assert.equal(iterator.next().value[1], "JavaScript (javascript, js, javascript, js)");
     assert.equal(
         iterator.next().value[1],
@@ -96,6 +100,10 @@ run_test("get_pygments_typeahead_list_for_settings", () => {
     );
     assert.equal(iterator.next().value[1], $t({defaultMessage: "Custom language: custom_lang"}));
     assert.equal(iterator.next().value[1], $t({defaultMessage: "Custom language: invent_a_lang"}));
+    assert.equal(iterator.next().value[1], "Text only (text, text)");
+    assert.equal(iterator.next().value[1], "quote (quote, quote)");
+    assert.equal(iterator.next().value[1], "spoiler (spoiler, spoiler)");
+    assert.equal(iterator.next().value[1], "math (math, math)");
     assert.equal(iterator.next().value[1], "JavaScript (javascript, js, javascript, js)");
     assert.equal(
         iterator.next().value[1],
@@ -107,9 +115,7 @@ run_test("get_pygments_typeahead_list_for_settings", () => {
     iterator = candidates.entries();
     assert.equal(iterator.next().value[1], $t({defaultMessage: "Custom language: invent_a_lang"}));
     assert.equal(iterator.next().value[1], $t({defaultMessage: "Custom language: custom_lang"}));
-    assert.equal(iterator.next().value[1], "JavaScript (javascript, js, javascript, js)");
-    assert.equal(
-        iterator.next().value[1],
-        "Python (python, bazel, py, py3, pyi, python3, sage, starlark, python, bazel, py, py3, pyi, python3, sage, starlark)",
-    );
+    assert.equal(iterator.next().value[1], "Text only (text, text)");
+    assert.equal(iterator.next().value[1], "quote (quote, quote)");
+    assert.equal(iterator.next().value[1], "spoiler (spoiler, spoiler)");
 });

web/tests/typeahead_helper.test.cjs

@@ -394,12 +394,15 @@ test("sort_streams", ({override, override_rewire}) => {
 
 function language_items(languages) {
     return languages.map((language) => ({
-        type: "syntax",
         language,
+        type: "syntax",
     }));
 }
 
-test("sort_languages", ({override_rewire}) => {
+test("sort_languages", ({override, override_rewire}) => {
+    override(realm, "realm_default_code_block_language", "dart");
+    const default_language = realm.realm_default_code_block_language;
+
     override_rewire(pygments_data, "langs", {
         python: {priority: 26},
         javascript: {priority: 27},
@@ -407,20 +410,52 @@ test("sort_languages", ({override_rewire}) => {
         pascal: {priority: 15},
         perl: {priority: 3},
         css: {priority: 21},
+        spoiler: {priority: 29},
+        text: {priority: 31},
+        quote: {priority: 30},
+        math: {priority: 28},
     });
 
-    let test_langs = language_items(["pascal", "perl", "php", "python", "javascript"]);
+    let test_langs = language_items(["pascal", "perl", "php", "python", "spoiler", "javascript"]);
     test_langs = th.sort_languages(test_langs, "p");
 
     // Sort languages by matching first letter, and then by popularity
-    assert.deepEqual(test_langs, language_items(["python", "php", "pascal", "perl", "javascript"]));
+    assert.deepEqual(
+        test_langs,
+        language_items(["python", "php", "pascal", "perl", "spoiler", "javascript"]),
+    );
 
     // Test if popularity between two languages are the same
     pygments_data.langs.php = {priority: 26};
-    test_langs = language_items(["pascal", "perl", "php", "python", "javascript"]);
+    test_langs = language_items(["pascal", "perl", "php", "python", "spoiler", "javascript"]);
     test_langs = th.sort_languages(test_langs, "p");
 
-    assert.deepEqual(test_langs, language_items(["php", "python", "pascal", "perl", "javascript"]));
+    assert.deepEqual(
+        test_langs,
+        language_items(["php", "python", "pascal", "perl", "spoiler", "javascript"]),
+    );
+
+    test_langs = language_items([
+        default_language,
+        "text",
+        "quote",
+        "math",
+        "python",
+        "javascript",
+    ]);
+    const test_langs_for_default = th.sort_languages(test_langs, "d");
+
+    assert.deepEqual(
+        test_langs_for_default,
+        language_items([default_language, "text", "quote", "math", "javascript", "python"]),
+    );
+
+    test_langs = th.sort_languages(test_langs, "t");
+
+    assert.deepEqual(
+        test_langs,
+        language_items(["text", "quote", "math", "javascript", "python", default_language]),
+    );
 });
 
 test("sort_languages on actual data", () => {