Revert "Implement debouncing to optimize text error handling"

It provided partial implementation only: for BesDOMService. What about
CKEditor?

This was optimizing something that users could "potentially" experience.
I didn't experience any performance problems on texts with hundreds of
grammar mistakes. Let alone a typical text users would have.

Skipping repositionAllMarkup() provides temporary misalignment between
markup and text. Performance vs. aesthetics?

Not convinced.

Reverts: 32f4360de9a5d2654a338ecf590d8f5f5cae2fec

service2.js

@@ -26,7 +26,6 @@ class BesService {
     this.hostElement = hostElement
     this.results = [] // Results of grammar-checking, one per each block/paragraph of text
     this.createCorrectionPanel()
-    this.firstCall = true
 
     // Disable browser built-in spell-checker to prevent collision with our grammar markup.
     this.originalSpellcheck = this.hostElement.spellcheck
@@ -778,16 +777,7 @@ class BesDOMService extends BesTreeService {
    */
   onInput() {
     // Now that the text is done changing, we can correctly calculate markup position.
-    // This is a way to resolve lagginess in repositioning markup with many mistakes.
-    if (this.firstCall) {
-      this.repositionAllMarkup()
-      this.firstCall = false
-    }
-    clearTimeout(this.debounceTimer)
-    this.debounceTimer = setTimeout(() => {
-      this.repositionAllMarkup()
-      this.firstCall = true
-    }, 300)
+    this.repositionAllMarkup()
 
     // Defer grammar-checking to reduce stress on grammar-checking server.
     this.timer = setTimeout(() => {