docs/control/fanctl/README.md: Fix MD026 warnings

The following warnings are generated by using markdownlint analysis:
```
docs/control/fanctl/README.md:60:12 MD026/no-trailing-punctuation Trailing punctuation in heading [Punctuation: ':']
```
Refer to markdown-lint [1] to fix MD026
[1]: https://github.com/updownpress/markdown-lint/blob/master/rules/026-no-trailing-punctuation.md

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: Icf87d4d60f406b0b936bddd98b7dbe91099ef58e
diff --git a/docs/control/fanctl/README.md b/docs/control/fanctl/README.md
index 0a38371..261a478 100644
--- a/docs/control/fanctl/README.md
+++ b/docs/control/fanctl/README.md
@@ -57,7 +57,7 @@
     - Display this help and exit
 ```
 
-## Examples:
+## Examples
 
 - Set all fans to a target value (The tool determines whether the machine is
   using RPM or PWM fan speeds, and sets them to the value provided):