Fix typo in Makefile (#52)

Author: santisoler

Diff for: Makefile

@@ -14,10 +14,10 @@ help:
 
 
 build:
-	msyt build --html
+	myst build --html
 
 clean:
-	msyt clean --all
+	myst clean --all
 
 run:
 	jupyter nbconvert --to notebook --execute --inplace "${NOTEBOOKS_DIR}/**/*.ipynb"

Diff for: README.md

@@ -51,7 +51,7 @@ preview it. Follow the instructions that will be prompted by the command to see
 the website:
 
 ```bash
-msyt start
+myst start
 ```
 
 #### Build only
@@ -60,7 +60,7 @@ The following command will build the website and store the HTML files in
 a new `_build` folder:
 
 ```bash
-msyt build --html
+myst build --html
 ```
 
 #### Clean cached builds