[override] Revise the override warning.

This change revises the override warning to make it easier to
interpretate.

Bug: 39636
Change-Id: Ib8bfb7604071d94b6c829bf581df6d6f0e375917
diff --git a/project/manifest.go b/project/manifest.go
index a8de3ce..be40f99 100644
--- a/project/manifest.go
+++ b/project/manifest.go
@@ -638,7 +638,7 @@
 			if revision == "" {
 				revision = "HEAD"
 			}
-			jirix.Logger.Warningf("Project %s(remote: %s) is overridden to revision %s, if this is not your intention, please run \"jiri override --delete %s %s\" to disable it.", v.Name, v.Remote, revision, v.Name, v.Remote)
+			jirix.Logger.Warningf("Project %s(remote: %s) is pinned to revision %s, if that is not what you want, please run \"jiri override --delete %s %s\" to unpin it.", v.Name, v.Remote, revision, v.Name, v.Remote)
 			jirix.OverrideWarned = true
 		}
 	}
@@ -648,7 +648,7 @@
 			if revision == "" {
 				revision = "HEAD"
 			}
-			jirix.Logger.Warningf("Import %s(remote: %s) is overridden to revision %s, if this is not your intention, please run \"jiri override --import-manifest=%s --delete %s %s\" to disable it.", v.Name, v.Remote, revision, v.Manifest, v.Name, v.Remote)
+			jirix.Logger.Warningf("Import %s(remote: %s) is pinned to revision %s, if that is not what you want, please run \"jiri override --import-manifest=%s --delete %s %s\" to unpin it.", v.Name, v.Remote, revision, v.Manifest, v.Name, v.Remote)
 			jirix.OverrideWarned = true
 		}
 	}