Update README.md (typos)

README.md

@@ -9,9 +9,9 @@ snmpEngineTime : The number of seconds since the value of the snmpEngineBoots ob
                  reverts to zero. This is a 32 bit integer counter (0..2147483647).
 ```
 
-**NOTE**: this is only a SNMP section that supersedes the original section "snmp_uptime". It will not touch the original check. You can control the usage of this section by disable/enable SNMP section "snmp_uptime_exetended"
+**NOTE**: this is only a SNMP section that supersedes the original section **_snmp_uptime_**. It will not touch the original check. You can control the usage of this section by disable/enable SNMP section **_snmp_uptime_exetended_**
 
-**NOTE**: this plugin my have some side efects on checks that use the original section and expect the uptime not larger than 497 days. I.e the interface inventory plugin ecpects this to calculate the "not used" state.
+**NOTE**: this plugin my have some side efects on checks that use the original section and expect the uptime not larger than 497 days. I.e the interface inventory plugin expects this to calculate the _not used_ state.
 
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