"score" text component does not accept names containing non-alphanumeric characters

The bug

When using the new "score" JSON text component, you cannot reference a name that contains non-alphanumeric characters. Hyphens, underscores, and periods are accepted.

Steps to reproduce

• Create a new scoreboard objective with a fake player containing a non-alphanumeric character:

  /scoreboard objectives add foo dummy
  /scoreboard players set "#example" foo 1
  

• Try to print the fake player's score value in chat:

  /tellraw @a {"rawtext":[{"score":{"name":"#example","objective":"foo"}}]}
  

→ Syntax error: Unexpected "#": at ">>#<<example"