doc: update assert.markdown

Update assert.throws() and assert.doesNotThrow() docs

doc/api/assert.markdown

@@ -39,7 +39,7 @@ Tests strict non-equality, as determined by the strict not equal operator ( `!==
 
 ## assert.throws(block, [error], [message])
 
-Expects `block` to throw an error. `error` can be constructor, regexp or 
+Expects `block` to throw an error. `error` can be constructor, `RegExp` or
 validation function.
 
 Validate instanceof using constructor:
@@ -76,7 +76,7 @@ Custom error validation:
 
 ## assert.doesNotThrow(block, [message])
 
-Expects `block` not to throw an error, see assert.throws for details.
+Expects `block` not to throw an error, see `assert.throws` for details.
 
 ## assert.ifError(value)