doc: fix trailing whitespace

Author: haramj

doc/api/cli.md

@@ -541,7 +541,7 @@ CPU.20190409.202950.15293.0.0.cpuprofile
 ```
 
 If `--cpu-prof-name` is specified, the provided value is used as a template
-for the file name. The following placeholder is supported and will be 
+for the file name. The following placeholder is supported and will be
 substituted at runtime:
 
 * `${pid}` — the current process ID