Update README.md

Author: cscheid

README.md

@@ -44,7 +44,7 @@ A robust parser for QMD documents will enable more robust treatment in editors,
 
 ## Important differences
 
-These is non-exhaustive and will only list intentional differences.
+These are non-exhaustive and will only list intentional differences.
 We will, aspirationally, treat unintentional differences as bugs.
 
 - no naked HTML support: use `{=html}` raw blocks an inlines
@@ -64,4 +64,4 @@ Parses [quarto-web](https://github.com/quarto-dev/quarto-web) with a small numbe
 - actually good error messages
 - fine-grained source location tracking
 - WASM distribution
-- solve glaring performance issues
+- solve glaring performance issues