gopls/internal/lsp/cache: keep analysis progress reports on one line

VS Code exposes only one line for progress reports; as pointed out in
golang/go#61352, multi-line reports cause a broken UI.

Fixes golang/go#61352

Change-Id: I0b5864f9a0dbb0bd9d191075b6c1cf0c7285f4bc
Reviewed-on: https://go-review.googlesource.com/c/tools/+/513735
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
gopls-CI: kokoro <noreply+kokoro@google.com>

gopls/internal/lsp/cache/analysis.go

@@ -354,8 +354,7 @@ func (snapshot *snapshot) Analyze(ctx context.Context, pkgs map[PackageID]unit,
 			if now.Sub(lastReport) > reportEvery {
 				lastReport = now
 				// Trailing space is intentional: some LSP clients strip newlines.
-				msg := fmt.Sprintf(`Constructing index of analysis facts... (%d/%d packages). 
-(Set "analysisProgressReporting" to false to disable notifications.)`,
+				msg := fmt.Sprintf(`Indexed %d/%d packages. (Set "analysisProgressReporting" to false to disable notifications.)`,
 					completed, len(nodes))
 				pct := 100 * float64(completed) / float64(len(nodes))
 				wd.Report(ctx, msg, pct)