Fix README typos (#1660)

README.md

@@ -2012,7 +2012,7 @@ while:
 
 ### Command Line Options
 
-`just` supports a number of useful command line options for listing, dumping, and debugging recipes and variable:
+`just` supports a number of useful command line options for listing, dumping, and debugging recipes and variables:
 
 ```sh
 $ just --list
@@ -2379,7 +2379,7 @@ foo argument:
   touch '{{argument}}'
 ```
 
-This preserves `just`'s ability to catch variable name typos before running, for example if you were to write `{{argument}}`, but will not do what you want if the value of `argument` contains single quotes.
+This preserves `just`'s ability to catch variable name typos before running, for example if you were to write `{{arument}}`, but will not do what you want if the value of `argument` contains single quotes.
 
 #### Positional Arguments