Add native Go method for finding pids to procstat (#3559)

plugins/inputs/procstat/README.md

@@ -27,8 +27,28 @@ Additionally the plugin will tag processes by their PID (pid_tag = true in the c
 * pid
 * process_name
 
+
+### Windows
+On windows we only support exe and pattern. Both of these are implemented using WMI queries. exe is on the Name field and pattern is on the CommandLine field.
+
+Windows Support:
+* exe  (WMI Name)
+* pattern (WMI CommandLine)
+
+this allows you to do fuzzy matching but only what is supported by [WMI query patterns](https://msdn.microsoft.com/en-us/library/aa392263(v=vs.85).aspx).
+
 Example:
 
+Windows fuzzy matching:
+```[[inputs.procstat]]
+  exe = "%influx%"
+  process_name="influxd"
+  prefix = "influxd"
+
+```
+
+### Linux
+
 ```
 [[inputs.procstat]]
   exe = "influxd"
@@ -48,7 +68,6 @@ The above configuration would result in output like:
 # Measurements
 Note: prefix can be set by the user, per process.
 
-
 Threads related measurement names:
 - procstat_[prefix_]num_threads value=5