MAINT: badge alt-text in README.md (#1380)

Update README.md

follow-up to #1377 to further standardize the badge alt-texts

Author: drammock

README.md

@@ -2,10 +2,10 @@
 
 [![License badge](https://img.shields.io/badge/License-BSD_3--Clause-yellow?logo=opensourceinitiative&logoColor=white)](https://github.com/pydata/pydata-sphinx-theme/blob/main/LICENSE)
 [![PyPI version badge](https://img.shields.io/pypi/v/pydata-sphinx-theme?logo=python&logoColor=white&color=orange)](https://pypi.org/project/pydata-sphinx-theme/)
-[![conda-forge license badge](https://img.shields.io/conda/vn/conda-forge/pydata-sphinx-theme.svg?logo=anaconda&logoColor=white&color=orange)](https://anaconda.org/conda-forge/pydata-sphinx-theme)
-[![GitHub Workflow Status - build](https://img.shields.io/github/actions/workflow/status/pydata/pydata-sphinx-theme/tests.yml?logo=github&logoColor=white)](https://github.com/pydata/pydata-sphinx-theme/actions/workflows/tests.yml)
-[![Read the Docs (version)](https://img.shields.io/readthedocs/pydata-sphinx-theme/latest?logo=readthedocs&logoColor=white)](https://readthedocs.org/projects/pydata-sphinx-theme/builds/)
-[![Codecov badge](https://img.shields.io/codecov/c/github/pydata/pydata-sphinx-theme?logo=codecov&logoColor=white)](https://codecov.io/gh/pydata/pydata-sphinx-theme)
+[![conda-forge version badge](https://img.shields.io/conda/vn/conda-forge/pydata-sphinx-theme.svg?logo=anaconda&logoColor=white&color=orange)](https://anaconda.org/conda-forge/pydata-sphinx-theme)
+[![GitHub Workflow test status badge](https://img.shields.io/github/actions/workflow/status/pydata/pydata-sphinx-theme/tests.yml?logo=github&logoColor=white)](https://github.com/pydata/pydata-sphinx-theme/actions/workflows/tests.yml)
+[![Read the Docs build status badge](https://img.shields.io/readthedocs/pydata-sphinx-theme/latest?logo=readthedocs&logoColor=white)](https://readthedocs.org/projects/pydata-sphinx-theme/builds/)
+[![Codecov test coverage percentage badge](https://img.shields.io/codecov/c/github/pydata/pydata-sphinx-theme?logo=codecov&logoColor=white)](https://codecov.io/gh/pydata/pydata-sphinx-theme)
 
 A clean, three-column, Bootstrap-based Sphinx theme by and for the [PyData community](https://pydata.org).