Updated code entry from -3pi/2 to -3pi/4 in tutorials/textbook/01_IQP…

…E.ipynb (Qiskit#1280)

* updated code entry from -3pi/2 to -3pi/4

* Updated code entry from -3pi/2 to -3pi/4

* added "\n" to the code of the images

* Fix Images built error

Images accidently being run in the file

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

tutorials/textbook/01_IQPE.ipynb

@@ -923,7 +923,7 @@
     "qc.p(-pi/4,0).c_if(c,1)\n",
     "\n",
     "qc.p(-pi/2,0).c_if(c,2)\n",
-    "qc.p(-3*pi/2,0).c_if(c,3)\n",
+    "qc.p(-3*pi/4,0).c_if(c,3)\n",
     "\n",
     "# c-U operations\n",
     "for _ in range(2**(m-3)):\n",