Update pipeline/inputs/mem-metrics.md

Co-authored-by: Lynette  Miles <6818907+esmerel@users.noreply.github.com>
Signed-off-by: Phillip Whelan <pwhelan@exis.cl>

Author: pwhelan

pipeline/inputs/mem-metrics.md

@@ -19,7 +19,7 @@ The `filter_pid` can include or be set to either `0` or `self` to refer to the f
 
 You can run the plugin from the command line or through a configuration file. By default metrics will be generated for all processes the current user can analyze.
 
-### Command Line
+### Command line
 
 ```bash
 $ fluent-bit -i mem_metrics -o stdout