Revert "FIX: word boundary regex (\b) not working in Unicode languages. (#9163)"

Lookbehind regex is not supported in Firefox or IE11

This reverts commit 572bb5988f.

test/javascripts/acceptance/search-test.js.es6

@@ -94,7 +94,7 @@ QUnit.test("Search with context", async assert => {
 
   const highlighted = [];
 
-  find("#post_7 span.highlighted").map((_, span) => {
+  find("#post_7 span.highlight-strong").map((_, span) => {
     highlighted.push(span.innerText);
   });
 

test/javascripts/lib/highlight-search-test.js.es6

@@ -1,48 +0,0 @@
-import highlightSearch, { CLASS_NAME } from "discourse/lib/highlight-search";
-import { fixture } from "helpers/qunit-helpers";
-
-QUnit.module("lib:highlight-search");
-
-QUnit.test("highlighting text", assert => {
-  fixture().html(
-    `
-    <p>This is some text to highlight</p>
-    `
-  );
-
-  highlightSearch(fixture(), "some text");
-
-  const terms = [];
-
-  fixture(`.${CLASS_NAME}`).each((_, elem) => {
-    terms.push(elem.textContent);
-  });
-
-  assert.equal(
-    terms.join(" "),
-    "some text",
-    "it should highlight the terms correctly"
-  );
-});
-
-QUnit.test("highlighting unicode text", assert => {
-  fixture().html(
-    `
-    <p>This is some தமிழ் and русский text to highlight</p>
-    `
-  );
-
-  highlightSearch(fixture(), "தமிழ் русский");
-
-  const terms = [];
-
-  fixture(`.${CLASS_NAME}`).each((_, elem) => {
-    terms.push(elem.textContent);
-  });
-
-  assert.equal(
-    terms.join(" "),
-    "தமிழ் русский",
-    "it should highlight the terms correctly"
-  );
-});

test/javascripts/lib/highlight-text-test.js.es6

@@ -0,0 +1,26 @@
+import highlightText, { CLASS_NAME } from "discourse/lib/highlight-text";
+import { fixture } from "helpers/qunit-helpers";
+
+QUnit.module("lib:highlight-text");
+
+QUnit.test("highlighting text", assert => {
+  fixture().html(
+    `
+    <p>This is some text to highlight</p>
+    `
+  );
+
+  highlightText(fixture(), "some text");
+
+  const terms = [];
+
+  fixture(`.${CLASS_NAME}`).each((_, elem) => {
+    terms.push(elem.textContent);
+  });
+
+  assert.equal(
+    terms.join(" "),
+    "some text",
+    "it should highlight the terms correctly"
+  );
+});