MarkdownToolbar: Bold: Add more tests

lib/widgets/markdown_toolbar.dart

@@ -110,6 +110,8 @@ TextEditingValue modifyCurrentWord(
   var wordStartPos = text.lastIndexOf(' ', cursorPos == 0 ? 0 : cursorPos - 1);
   if (wordStartPos == -1) {
     wordStartPos = 0;
+  } else {
+    wordStartPos += 1;
   }
 
   var wordEndPos = text.indexOf(' ', cursorPos);

test/markdown_toolbar_test.dart

@@ -146,4 +146,24 @@ void main() {
       char: '**',
     );
   });
+
+  test("Surrounds the middle word", () {
+    _testWord(
+      before: 'Hello Hydra Person',
+      beforeOffset: 8,
+      after: 'Hello **Hydra** Person',
+      afterOffset: 13,
+      char: '**',
+    );
+  });
+
+  test("Removes the middle word", () {
+    _testWord(
+      before: 'Hello **Hydra** Person',
+      beforeOffset: 9,
+      after: 'Hello Hydra Person',
+      afterOffset: 11,
+      char: '**',
+    );
+  });
 }