feat(amazonq): Support pre-release LSP versions (#6539)

## Problem
We can't consume prerelease versions from the gamma manifest

## Solution
Support pre release lsp versions + test

## Notes
- I'll have another PR soon that pulls out the configuration so we can
switch manifest urls for testing pretty easily
- E2E tests won't work until
#6538 is merged


---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Author: jpinkney-aws

packages/amazonq/src/lsp/lspInstaller.ts

@@ -4,7 +4,6 @@
  */
 
 import * as vscode from 'vscode'
-import { Range } from 'semver'
 import {
     ManifestResolver,
     LanguageServerResolver,
@@ -15,9 +14,12 @@ import {
     cleanLspDownloads,
 } from 'aws-core-vscode/shared'
 import path from 'path'
+import { Range } from 'semver'
 
-const manifestURL = 'https://aws-toolkit-language-servers.amazonaws.com/codewhisperer/0/manifest.json'
-export const supportedLspServerVersions = '^3.1.1'
+export const manifestURL = 'https://aws-toolkit-language-servers.amazonaws.com/codewhisperer/0/manifest.json'
+export const supportedLspServerVersions = new Range('^3.1.1', {
+    includePrerelease: true,
+})
 
 export class AmazonQLSPResolver implements LspResolver {
     async resolve(): Promise<LspResolution> {
@@ -41,7 +43,7 @@ export class AmazonQLSPResolver implements LspResolver {
         const installationResult = await new LanguageServerResolver(
             manifest,
             name,
-            new Range(supportedLspServerVersions)
+            supportedLspServerVersions
         ).resolve()
 
         const nodePath = path.join(installationResult.assetDirectory, `servers/${getNodeExecutableName()}`)

packages/amazonq/test/e2e/lsp/lspInstaller.test.ts

@@ -5,7 +5,7 @@
 
 import assert from 'assert'
 import sinon from 'sinon'
-import { AmazonQLSPResolver, supportedLspServerVersions } from '../../../src/lsp/lspInstaller'
+import { AmazonQLSPResolver, manifestURL, supportedLspServerVersions } from '../../../src/lsp/lspInstaller'
 import {
     fs,
     globals,
@@ -225,5 +225,38 @@ describe('AmazonQLSPInstaller', () => {
 
             assertTelemetry('languageServer_setup', expectedTelemetry)
         })
+
+        it('resolves release candidiates', async () => {
+            const original = new ManifestResolver(manifestURL, 'AmazonQ').resolve()
+            sandbox.stub(ManifestResolver.prototype, 'resolve').callsFake(async () => {
+                const originalManifest = await original
+
+                const latestVersion = originalManifest.versions.reduce((latest, current) => {
+                    return semver.gt(current.serverVersion, latest.serverVersion) ? current : latest
+                }, originalManifest.versions[0])
+
+                // These convert something like 3.1.1 to 3.2.1-rc.0
+                const incrementedVersion = semver.inc(latestVersion.serverVersion, 'minor')
+                if (!incrementedVersion) {
+                    assert.fail('Failed to increment minor version')
+                }
+
+                const prereleaseVersion = semver.inc(incrementedVersion, 'prerelease', 'rc')
+                if (!prereleaseVersion) {
+                    assert.fail('Failed to create pre-release version')
+                }
+
+                const newVersion = {
+                    ...latestVersion,
+                    serverVersion: prereleaseVersion,
+                }
+
+                originalManifest.versions = [newVersion, ...originalManifest.versions]
+                return originalManifest
+            })
+
+            const download = await resolver.resolve()
+            assert.ok(download.assetDirectory.endsWith('-rc.0'))
+        })
     })
 })

packages/core/src/shared/lsp/lspResolver.ts

@@ -345,7 +345,11 @@ export class LanguageServerResolver {
             return false
         }
 
-        return semver.satisfies(version.serverVersion, this.versionRange) && !version.isDelisted
+        return (
+            semver.satisfies(version.serverVersion, this.versionRange, {
+                includePrerelease: true,
+            }) && !version.isDelisted
+        )
     }
 
     /**