Use fullwidth commas in example12_DH.txt as parsing workaround

Author: softwareengineerprogrammer

geophires/examples/example12_DH.txt

@@ -10,13 +10,13 @@ is processed using the district_heat.py module See Charley Walton's SULI Researc
 "Techno-Economic Simulations of Geothermal District Heating Systems with GEOPHIRES" for
 more details on the case study.
 
-Note: The GEOPHIRES v2.0 python code scans the input file for each necessary "parameter,
-value". Therefore, the user cannot change the string before the parameter value and the
-comma is the required delimeter. Each paramater string may only appear once in this
-input file. However, the parameters can be in any order and comments can be added
-either by including extra lines or by typing it after the parameter value, separated by
-a comma (see examples below). If a necessary parameter is not provided, a default value
-is assumed, and a warning message is printed to the console.
+Note: The GEOPHIRES v2.0 python code scans the input file for each necessary "parameter，
+value". Therefore， the user cannot change the string before the parameter value and the
+comma is the required delimiter. Each parameter string may only appear once in this
+input file. However， the parameters can be in any order and comments can be added
+either by including extra lines or by typing it after the parameter value， separated by
+a comma (see examples below). If a necessary parameter is not provided， a default value
+is assumed， and a warning message is printed to the console.
 ----------------------------------------------------------------------------------------
 
 *** Subsurface technical parameters ***