fix(curriculum): add multiple quiz sets available to quiz intro (freeCodeCamp#59361)

Co-authored-by: Tom <[email protected]>

Author: Supravisor

client/i18n/locales/english/intro.json

@@ -1869,7 +1869,8 @@
       "quiz-basic-html": {
         "title": "Basic HTML Quiz",
         "intro": [
-          "The following quiz will test your knowledge of the basic HTML concepts you have learned so far."
+          "The following quiz will test your knowledge of the basic HTML concepts you have learned so far.",
+          "If you're getting ready for the exam, there are several quiz sets available for practice. After completing a quiz, you can revisit this page to access a new set of questions."
         ]
       },
       "lecture-importance-of-semantic-html": {
@@ -1900,7 +1901,8 @@
       "quiz-semantic-html": {
         "title": "Semantic HTML Quiz",
         "intro": [
-          "The following quiz will test your knowledge on semantic HTML concepts you have learned so far."
+          "The following quiz will test your knowledge on semantic HTML concepts you have learned so far.",
+          "If you're getting ready for the exam, there are several quiz sets available for practice. After completing a quiz, you can revisit this page to access a new set of questions."
         ]
       },
       "lecture-working-with-forms": {
@@ -1958,7 +1960,8 @@
       "quiz-html-tables-and-forms": {
         "title": "HTML Tables and Forms Quiz",
         "intro": [
-          "The following quiz will test your knowledge of HTML tables, forms and commonly used HTML tools."
+          "The following quiz will test your knowledge of HTML tables, forms and commonly used HTML tools.",
+          "If you're getting ready for the exam, there are several quiz sets available for practice. After completing a quiz, you can revisit this page to access a new set of questions."
         ]
       },
       "lecture-importance-of-accessibility-and-good-html-structure": {
@@ -1984,7 +1987,8 @@
       "quiz-html-accessibility": {
         "title": "HTML Accessibility Quiz",
         "intro": [
-          "The following quiz will test your knowledge on the accessibility concepts you have learned so far."
+          "The following quiz will test your knowledge on the accessibility concepts you have learned so far.",
+          "If you're getting ready for the exam, there are several quiz sets available for practice. After completing a quiz, you can revisit this page to access a new set of questions."
         ]
       },
       "review-html": {