Update source_code languages in README

[mikehaller]

Although C++ is mentioned very prominently, it's actually not supported by all macros - especially not by the dash license checker.

Hence, extending the readme to clearly show that C++ is not yet supported.

[github-actions]

License Check Results

🚀 The license check job ran with the Bazel command:

bazel run //:license-check

Status: ⚠️ Needs Review

Click to expand output

[License Check Output]
2025/12/19 12:17:29 Downloading https://releases.bazel.build/8.3.0/release/bazel-8.3.0-linux-x86_64...
Extracting Bazel installation...
Starting local Bazel server (8.3.0) and connecting to it...
INFO: Invocation ID: 7ac0165c-905d-4bd9-ae83-6d9aec301062
Computing main repo mapping: 
Computing main repo mapping: 
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Computing main repo mapping: 
Loading: 
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Analyzing: target //:license-check (1 packages loaded, 0 targets configured)
Analyzing: target //:license-check (1 packages loaded, 0 targets configured)

Analyzing: target //:license-check (22 packages loaded, 9 targets configured)

Analyzing: target //:license-check (74 packages loaded, 9 targets configured)

Analyzing: target //:license-check (102 packages loaded, 192 targets configured)

Analyzing: target //:license-check (136 packages loaded, 2411 targets configured)

Analyzing: target //:license-check (141 packages loaded, 2469 targets configured)

Analyzing: target //:license-check (141 packages loaded, 2470 targets configured)

Analyzing: target //:license-check (141 packages loaded, 2470 targets configured)

Analyzing: target //:license-check (141 packages loaded, 2470 targets configured)

Analyzing: target //:license-check (147 packages loaded, 4603 targets configured)

Analyzing: target //:license-check (148 packages loaded, 4723 targets configured)

Analyzing: target //:license-check (148 packages loaded, 4723 targets configured)

Analyzing: target //:license-check (148 packages loaded, 4723 targets configured)

Analyzing: target //:license-check (148 packages loaded, 4723 targets configured)

INFO: Analyzed target //:license-check (149 packages loaded, 6658 targets configured).
[9 / 13] checking cached actions
[9 / 13] JavaToolchainCompileClasses external/rules_java+/toolchains/platformclasspath_classes; 0s disk-cache, processwrapper-sandbox
INFO: From Generating Dash formatted dependency file ...:
INFO: Successfully converted 2 packages from Cargo.lock to bazel-out/k8-fastbuild/bin/formatted.txt
[11 / 13] JavaToolchainCompileBootClasspath external/rules_java+/toolchains/platformclasspath.jar; 0s disk-cache, processwrapper-sandbox
[12 / 13] Building license.check.license_check.jar (); 0s disk-cache, multiplex-worker
INFO: Found 1 target...
Target //:license.check.license_check up-to-date:
  bazel-bin/license.check.license_check
  bazel-bin/license.check.license_check.jar
INFO: Elapsed time: 206.049s, Critical Path: 2.67s
INFO: 13 processes: 9 internal, 3 processwrapper-sandbox, 1 worker.
INFO: Build completed successfully, 13 total actions
INFO: Running command line: bazel-bin/license.check.license_check ./formatted.txt <args omitted>
usage: org.eclipse.dash.licenses.cli.Main [-batch <int>] [-cd <url>]
       [-confidence <int>] [-ef <url>] [-excludeSources <sources>] [-help] [-lic
       <url>] [-project <shortname>] [-repo <url>] [-review] [-summary <file>]
       [-timeout <seconds>] [-token <token>]

[github-actions]

The created documentation from the pull request is available at: docu-html

[FScholPer]

This should be the template for everything. C++ is a must. Then we have to use another licence checker which supports c++ and not change the readme. @AlexanderLanin can you please check