Merge pull request #2457 from PSLmodels/MattHJensen-patch-1

correct liebility typo in overview.md

docs/usage/overview.md

@@ -43,7 +43,7 @@ reform.
 *   `calc_all()` → Calculator class method that computes tax liability
 (and many intermediate variables such as AGI) for each filing-unit.
 
-*   `itax_clp` → Variable containing aggregate income tax liebility under
+*   `itax_clp` → Variable containing aggregate income tax liability under
 current-law policy.  
     Created by `weighted_total('iitax')` method called on `calc_clp` object
     after `calc_all()` called.
@@ -123,4 +123,4 @@ required to calculate income and payroll tax liability for each filing unit.
 ### Utilities
 
 Documentation and source code for the global utility functions are in
-[utils.py](https://github.com/PSLmodels/Tax-Calculator/blob/master/taxcalc/utils.py).
+[utils.py](https://github.com/PSLmodels/Tax-Calculator/blob/master/taxcalc/utils.py).