fix(completion): prev text with uppercase should match

Closes #4764

Author: chemzqm

src/completion/complete.ts

@@ -293,7 +293,7 @@ export default class Complete {
           if (item.delta > 0) {
             // better input to make it have higher score and better highlight
             let prev = filterText.slice(0, item.delta)
-            fuzzyResult = scoreFn(prev + input, prev + lowInput, 0, filterText, filterText.toLowerCase(), 0, scoreOption)
+            fuzzyResult = scoreFn(prev + input, prev.toLowerCase() + lowInput, 0, filterText, filterText.toLowerCase(), 0, scoreOption)
           } else {
             fuzzyResult = scoreFn(input, lowInput, 0, filterText, filterText.toLowerCase(), 0, scoreOption)
           }

src/completion/pum.ts

@@ -9,7 +9,7 @@ import { toNumber } from '../util/numbers'
 import { byteIndex, byteLength, characterIndex, toText } from '../util/string'
 import workspace from '../workspace'
 import { CompleteOption, DurationCompleteItem } from './types'
-import { getKindHighlight, getKindText, highlightOffert, MruLoader, Selection } from './util'
+import { getKindHighlight, getKindText, highlightOffset, MruLoader, Selection } from './util'
 
 export interface PumDimension {
   readonly height: number
@@ -277,7 +277,7 @@ export default class PopupMenu {
       switch (name) {
         case 'abbr': {
           if (!isFalsyOrEmpty(item.positions)) {
-            let pre = highlightOffert(len, item)
+            let pre = highlightOffset(len, item)
             if (pre != -1) {
               positionHighlights(hls, item.abbr, item.positions, pre, index, labelMaxLength)
             } else {

src/completion/util.ts

@@ -260,7 +260,7 @@ export function shouldIndent(indentkeys: string, pretext: string): boolean {
   return false
 }
 
-export function highlightOffert<T extends { filterText: string, abbr: string }>(pre: number, item: T): number {
+export function highlightOffset<T extends { filterText: string, abbr: string }>(pre: number, item: T): number {
   let { filterText, abbr } = item
   let idx = abbr.indexOf(filterText)
   if (idx == -1) return -1