[gopls-release-branch.0.18] gopls/internal/settings: fix misleading error messages

The deprecatedError helper constructs a specifically formatted error
string suggesting a replacement. Certain deprecations were misusing the
API, resulting in nonsensical error messages.

Change-Id: Ic72bf608b5b2e97baf75c192a49fd4181d7800b2
Reviewed-on: https://go-review.googlesource.com/c/tools/+/651695
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Alan Donovan <[email protected]>
(cherry picked from commit 5299dcb)
Reviewed-on: https://go-review.googlesource.com/c/tools/+/651696
Auto-Submit: Robert Findley <[email protected]>

Author: findleyr

gopls/internal/settings/settings.go

@@ -1116,15 +1116,15 @@ func (o *Options) setOne(name string, value any) (applied []CounterPath, _ error
 			return nil, err
 		}
 		if o.Analyses["fieldalignment"] {
-			return counts, deprecatedError("the 'fieldalignment' analyzer was removed in gopls/v0.17.0; instead, hover over struct fields to see size/offset information (https://go.dev/issue/66861)")
+			return counts, &SoftError{"the 'fieldalignment' analyzer was removed in gopls/v0.17.0; instead, hover over struct fields to see size/offset information (https://go.dev/issue/66861)"}
 		}
 		return counts, nil
 
 	case "hints":
 		return setBoolMap(&o.Hints, value)
 
 	case "annotations":
-		return nil, deprecatedError("the 'annotations' setting was removed in gopls/v0.18.0; all compiler optimization details are now shown")
+		return nil, &SoftError{"the 'annotations' setting was removed in gopls/v0.18.0; all compiler optimization details are now shown"}
 
 	case "vulncheck":
 		return setEnum(&o.Vulncheck, value,