update exploration costs tooltip from theoretical basis (previous version was missing M for geophysical aand field work)

Author: softwareengineerprogrammer

src/geophires_x/Economics.py

@@ -1852,7 +1852,8 @@ def __init__(self, model: Model):
             UnitType=Units.CURRENCY,
             PreferredUnits=CurrencyUnit.MDOLLARS,
             CurrentUnits=CurrencyUnit.MDOLLARS,
-            ToolTipText=f'Default correlation: 60% of the cost of one production well '
+            ToolTipText=f'The built-in exploration cost correlation considers drilling of a slim-hole well at 60% of '
+                        f'the cost of a regular well, $1M for geophysical and field work, '
                         f'{contingency_and_indirect_costs_tooltip}. '
                         f'Provide {self.ccexpladjfactor.Name} to multiply the default correlation. '
                         f'Provide {self.ccexplfixed.Name} to override the default correlation and set your own cost.'

src/geophires_x_schema_generator/geophires-result.json

@@ -430,7 +430,7 @@
         "Total surface equipment costs": {},
         "Exploration costs": {
           "type": "number",
-          "description": "Exploration cost. Default correlation: 60% of the cost of one production well plus 15% contingency plus 12% indirect costs. Provide Exploration Capital Cost Adjustment Factor to multiply the default correlation. Provide Exploration Capital Cost to override the default correlation and set your own cost.",
+          "description": "Exploration cost. The built-in exploration cost correlation considers drilling of a slim-hole well at 60% of the cost of a regular well, $1M for geophysical and field work, plus 15% contingency plus 12% indirect costs. Provide Exploration Capital Cost Adjustment Factor to multiply the default correlation. Provide Exploration Capital Cost to override the default correlation and set your own cost.",
           "units": "MUSD"
         },
         "Investment Tax Credit": {