[projmgr] Improve filter help text

[brondani]

Fixes

• Help text change #2478

Checklist

• 🤖 This change is covered by unit tests (if applicable).
• 🤹 Manual testing has been performed (if necessary).
• 🛡️ Security impacts have been considered (if relevant).
• 📖 Documentation updates are complete (if required).
• 🧠 Third-party dependencies and TPIP updated (if required).

[github-actions]

Test Results

    3 files   -    55     21 suites   - 155   20m 7s ⏱️ - 5m 22s
  464 tests  -   451    464 ✅  -   434  0 💤  - 17  0 ❌ ±0 
1 392 runs   - 1 490  1 392 ✅  - 1 422  0 💤  - 68  0 ❌ ±0 

Results for commit ff8c6fb. ± Comparison against base commit 67cb104.

This pull request removes 451 tests.

AuxCmdTests ‑ MkdirCmdTest
AuxCmdTests ‑ RmdirCmdTest
AuxCmdTests ‑ TouchCmdTest
BuildSystemGeneratorTests ‑ GenAuditFile
BuildSystemGeneratorTests ‑ GenAuditFile_WithOut_Existing_Audit_File
BuildSystemGeneratorTests ‑ GenAuditFile_With_Existing_Audit_File
BuildSystemGeneratorTests ‑ GetString
BuildSystemGeneratorTests ‑ StrConv
BuildSystemGeneratorTests ‑ StrNorm
CBuildGCCTests ‑ Asm
…

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.23%. Comparing base (67cb104) to head (ff8c6fb).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2481   +/-   ##
=======================================
  Coverage   65.23%   65.23%           
=======================================
  Files         147      147           
  Lines       26659    26659           
  Branches    16155    16155           
=======================================
  Hits        17390    17390           
  Misses       7074     7074           
  Partials     2195     2195           

Flag	Coverage Δ
projmgr-cov	87.92% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
tools/projmgr/src/ProjMgr.cpp	86.28% <100.00%> (ø)

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