fixed heading and bold text in rst

Author: davidsebfischer

README.rst

@@ -6,14 +6,14 @@
    :target: https://diffxpy.readthedocs.io
 
 Fast and scalable differential expression analysis on single-cell RNA-seq data
-===
+==============================================================================
 
 diffxpy covers a wide range of differential expression analysis scenarios encountered in single-cell RNA-seq scenarios
 and integrates into scanpy_ workflows.
 Import diffxpy as `import diffxpy.api as de` to access the following differential expression analysis-related tools:
 
-1. _differential expression analysis_ in the module `de.test.*`
-2. _gene set enrichment analysis_ based on differential expression calls in the module  `de.enrich.*`
+1. **differential expression analysis** in the module `de.test.*`
+2. **gene set enrichment analysis** based on differential expression calls in the module  `de.enrich.*`
 
 Refer to the documentation_ and the tutorials_ for details of these modules.