docs(issues): rename and link issue spec 1525-01 to GitHub issue #1703

- Renamed docs/issues/1525-01-persistence-test-coverage.md to
  docs/issues/1703-1525-01-persistence-test-coverage.md to align the
  file name with the tracked GitHub issue number
- Updated the spec title to include the issue number (#1703) and added
  a link to #1703
- Updated the spec file reference in docs/issues/1525-overhaul-persistence.md
  to point to the renamed file

Author: josecelano

docs/issues/1525-overhaul-persistence.md

@@ -86,7 +86,7 @@ You can then browse or search it while working in the main repository.
 
 ### 1) Add DB compatibility matrix
 
-- Spec file: `docs/issues/1525-01-persistence-test-coverage.md`
+- Spec file: `docs/issues/1703-1525-01-persistence-test-coverage.md`
 - Outcome: compatibility matrix exercises SQLite and multiple MySQL versions; PostgreSQL slot
   reserved for subissue 8
 

…ues/1525-01-persistence-test-coverage.md …703-1525-01-persistence-test-coverage.mddocs/issues/1525-01-persistence-test-coverage.md renamed to docs/issues/1703-1525-01-persistence-test-coverage.md docs/issues/1525-01-persistence-test-coverage.md renamed to docs/issues/1703-1525-01-persistence-test-coverage.md

@@ -1,4 +1,6 @@
-# Subissue Draft for #1525-01: Add DB Compatibility Matrix
+# Subissue #1703 (Draft for #1525-01): Add DB Compatibility Matrix
+
+- Issue: https://github.com/torrust/torrust-tracker/issues/1703
 
 ## Goal