Remove @author tags (#5601)

Our files are up to a decade old, and have churned so much, that the initial author of the file no longer has much meaning.

Furthermore, this will encourage developers to post to the developer group, rather than emailing Googlers (usually me) directly.

demos/custom-fields/pitch/blocks.js

@@ -6,7 +6,6 @@
 
 /**
  * @fileoverview Pitch field demo blocks.
- * @author samelh@gmail.com (Sam El-Husseini)
  */
 
 Blockly.Blocks['test_pitch_field'] = {

demos/custom-fields/pitch/field_pitch.js

@@ -7,8 +7,6 @@
 
 /**
  * @fileoverview Music pitch input field. Borrowed from Blockly Games.
- * @author fraser@google.com (Neil Fraser)
- * @author samelh@google.com (Sam El-Husseini)
  */
 'use strict';
 

demos/custom-fields/turtle/blocks.js

@@ -6,7 +6,6 @@
 
 /**
  * @fileoverview Turtle field demo blocks.
- * @author bekawestberg@gmail.com (Beka Westberg)
  */
 
 Blockly.Blocks['turtle_basic'] = {

demos/custom-fields/turtle/field_turtle.js

@@ -6,7 +6,6 @@
 
 /**
  * @fileoverview A field used to customize a turtle.
- * @author bekawestberg@gmail.com (Beka Westberg)
  */
 'use strict';