Mark long-deprecated and unused constants for removal

[nburnwal09]

There are few constants in PDE that have been deprecated for a long time and are no longer referenced within the codebase.
This change adds Deprecated tags for those to indicate their planned removal in a future release.

[github-actions]

Test Results

  147 files  ±0    147 suites  ±0   36m 38s ⏱️ + 1m 16s
3 493 tests ±0  3 439 ✅ ±0   54 💤 ±0  0 ❌ ±0 
9 303 runs  ±0  9 173 ✅ ±0  130 💤 ±0  0 ❌ ±0 

Results for commit 9c500fa. ± Comparison against base commit bc2c838.

♻️ This comment has been updated with latest results.

[eclipse-pde-bot]

This pull request changes some projects for the first time in this development cycle.
Therefore the following files need a version increment:

ui/org.eclipse.pde.launching/META-INF/MANIFEST.MF

An additional commit containing all the necessary changes was pushed to the top of this PR's branch. To obtain these changes (for example if you want to push more changes) either fetch from your fork or apply the git patch.

Git patch

From 9dd22b0303560f1aebfeaeccb9fb13d345ebd614 Mon Sep 17 00:00:00 2001
From: Eclipse PDE Bot <pde-bot@eclipse.org>
Date: Tue, 6 Jan 2026 05:20:03 +0000
Subject: [PATCH] Version bump(s) for 4.39 stream


diff --git a/ui/org.eclipse.pde.launching/META-INF/MANIFEST.MF b/ui/org.eclipse.pde.launching/META-INF/MANIFEST.MF
index 45e9365482..4d331f7d01 100644
--- a/ui/org.eclipse.pde.launching/META-INF/MANIFEST.MF
+++ b/ui/org.eclipse.pde.launching/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %name
 Bundle-SymbolicName: org.eclipse.pde.launching;singleton:=true
-Bundle-Version: 3.13.600.qualifier
+Bundle-Version: 3.13.700.qualifier
 Bundle-RequiredExecutionEnvironment: JavaSE-17
 Bundle-Vendor: %provider-name
 Require-Bundle: org.eclipse.jdt.junit.core;bundle-version="[3.6.0,4.0.0)",
-- 
2.52.0

Further information are available in Common Build Issues - Missing version increments.

[nburnwal09]

@laeubi
Could you pls review this PR?

[nburnwal09]

Hi @iloveeclipse
Could you please check this PR when you get time.?