Fix repo name resolver cache miss due to using separate RepoNameResol… (

#6570)

We were creating a separate instance of the RepoNameResolver which was
causing cache miss and in return making graphql calls to fetch the repo
name.

RepoNameResolver internally maintains an LRU and is supposed to be a
singelton.

## Test plan

- monitor network to check getRepoName queries are not made everytime
you press @.
- 
## Changelog

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vscode/src/editor/utils/editor-context.ts

@@ -31,7 +31,7 @@ import {
 import { URI } from 'vscode-uri'
 import { getOpenTabsUris } from '.'
 import { toVSCodeRange } from '../../common/range'
-import { RepoNameResolver } from '../../repository/repo-name-resolver'
+import { repoNameResolver } from '../../repository/repo-name-resolver'
 import { findWorkspaceFiles } from './findWorkspaceFiles'
 
 // Some matches we don't want to ignore because they might be valid code (for example `bin/` in Dart)
@@ -319,7 +319,6 @@ async function createContextFileFromUri(
     symbolName?: string
 ): Promise<ContextItem[]> {
     const range = toRangeData(selectionRange)
-    const repoNameResolver = new RepoNameResolver()
     const repoNames = await firstValueFrom(repoNameResolver.getRepoNamesContainingUri(uri))
     const repoName: string = Array.isArray(repoNames) ? repoNames[0] : repoNames.toString()