Fix typo and update robot custom script rule documentation

Change-Id: If81edc1133966f3e55316b7572ebc955364699ef
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/ipmi/test_ipmi_sel.robot b/ipmi/test_ipmi_sel.robot
index 3eaa3de..a9262a3 100644
--- a/ipmi/test_ipmi_sel.robot
+++ b/ipmi/test_ipmi_sel.robot
@@ -29,7 +29,7 @@
     [Documentation]  Verify IPMI sel clear command clears the SEL entry.
     [Tags]  Verify_Empty_SEL
 
-    # Generate an error log and verify there is one atleast.
+    # Generate an error log and verify there is one at least.
     Create Test PEL Log
     ${resp}=  Run IPMI Standard Command  sel elist last 1
     Log To Console  ${resp}
diff --git a/robot_custom_rules.py b/robot_custom_rules.py
index ef10c84..b71b289 100644
--- a/robot_custom_rules.py
+++ b/robot_custom_rules.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 # Custom rules file for robotframework-lint.
-# Example usage: python -m rflint -rA robot_standards -R robot_custom_rules.py .
+# Installation : pip3 install --upgrade robotframework-lint
+# Example usage: python3 -m rflint -rA robot_standards -R robot_custom_rules.py .
 import re
 from rflint.common import SuiteRule, ERROR