remove: remove nancount from namespace

This commit removes the `nancount` symbol from the `@stdlib/stats/strided`
namespace due to a package migration.

BREAKING CHANGE: remove `nancount`

To migrate, users should access the equivalent symbol `gnancount` via the
`@stdlib/blas/ext/base` namespace.

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
report:
  - task: lint_filenames
    status: passed
  - task: lint_editorconfig
    status: passed
  - task: lint_markdown
    status: na
  - task: lint_package_json
    status: na
  - task: lint_repl_help
    status: na
  - task: lint_javascript_src
    status: passed
  - task: lint_javascript_cli
    status: na
  - task: lint_javascript_examples
    status: na
  - task: lint_javascript_tests
    status: na
  - task: lint_javascript_benchmarks
    status: na
  - task: lint_python
    status: na
  - task: lint_r
    status: na
  - task: lint_c_src
    status: na
  - task: lint_c_examples
    status: na
  - task: lint_c_benchmarks
    status: na
  - task: lint_c_tests_fixtures
    status: na
  - task: lint_shell
    status: na
  - task: lint_typescript_declarations
    status: passed
  - task: lint_typescript_tests
    status: na
  - task: lint_license_headers
    status: passed
---

Author: kgryte

lib/node_modules/@stdlib/stats/strided/lib/index.js

@@ -1179,15 +1179,6 @@ setReadOnly( ns, 'mskminabs', require( '@stdlib/stats/strided/mskminabs' ) );
 */
 setReadOnly( ns, 'mskrange', require( '@stdlib/stats/strided/mskrange' ) );
 
-/**
-* @name nancount
-* @memberof ns
-* @readonly
-* @type {Function}
-* @see {@link module:@stdlib/stats/strided/nancount}
-*/
-setReadOnly( ns, 'nancount', require( '@stdlib/stats/strided/nancount' ) );
-
 /**
 * @name nanmax
 * @memberof ns