Update index.md

[sleblang]

Under the heading - Step 5: Write your stories

• Sample Angular doc code adds two instances of emoji button component rather than an instance of a text button component (see line 133)

Issue:

• Sample code for text button component in Angular doc is incorrect - showing emoji code;

What I did

• Added in text button sample code from demo angular project;

How to test

• Is this testable with Jest or Chromatic screenshots?
• Does this need a new example in the kitchen sink apps?
• Does this need an update to the documentation?

If your answer is yes to any of these, please make sure to include it in your PR.

[codecov]

Codecov Report

Merging #6333 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6333   +/-   ##
=======================================
  Coverage   35.06%   35.06%           
=======================================
  Files         636      636           
  Lines        9366     9366           
  Branches     1320     1320           
=======================================
  Hits         3284     3284           
  Misses       5436     5436           
  Partials      646      646

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c6377ab...d2a2d08. Read the comment docs.

[shilman]

Thanks!