Detect unquoted password values in C# connection strings

[Saharsh1123]

• Please check if the PR fulfills these requirements

• Tests for the changes have been added

• Docs have been added / updated

• All CI checks are green

• What kind of change does this PR introduce?
  Bug fix.

• What is the current behavior?
  C# connection strings containing an unquoted password field, such as:

String oraConnStr = "Data Source=sis2:1521/dprod.sis2.domain.org;User ID=svcacct;Password=svcacctpass;";

are not detected by the keyword plugin.

Fixes #699.

• What is the new behavior (if this is a feature change)?
  The keyword plugin now detects C# connection-string-style keyword=value; password fields and extracts the password value.

This adds coverage for the reported Password=svcacctpass; case while preserving existing C / Objective-C behavior that requires quoted values for normal C-style assignments.

• Does this PR introduce a breaking change?
  No.

• Other information:
  Tested locally with:

• python -m pytest tests/plugins/keyword_test.py
• python -m pytest tests
• python -m pytest