DOC: Readme: Reduce subheading size

Author: kernc

README.md

@@ -49,15 +49,16 @@ Usage: diff-logs < FILE1.log           # Print log file diff-friendly
 
 Examples
 --------
-### Diff two log files
+
+#### Diff two log files
 ```shell
 diff-logs FILE1 FILE2    # Invokes `diff`
 # or
 export DIFFTOOL=meld
 diff-logs FILE1 FILE2    # Invokes `meld`
 ```
 
-### Diff-friendly-format a single log file
+#### Diff-friendly-format a single log file
 ```shell
 diff-logs < FILE1 > FILE1.clean
 ```