fix: Widen {v,h}space to int | str

[dangotbanned]

Follow-up to #1068, which fixes the last 7 diagnostics from ty on the examples:

Show diagnostics

uv run --group dev ty check ../../../docs/public/specs/python/

error[invalid-argument-type]: Argument to function `hspace` is incorrect
  --> /mosaic/docs/public/specs/python/aeromagnetic-survey.py:15:19
   |
15 |         vg.hspace("1em"),
   |                   ^^^^^ Expected `int`, found `Literal["1em"]`
   |
info: Function defined here
   --> vgplot/plot.py:189:5
    |
189 | def hspace(px: int) -> Any:
    |     ^^^^^^ ------- Parameter declared here
    |

error[invalid-argument-type]: Argument to function `vspace` is incorrect
  --> /mosaic/docs/public/specs/python/aeromagnetic-survey.py:18:15
   |
18 |     vg.vspace("1em"),
   |               ^^^^^ Expected `int`, found `Literal["1em"]`
   |
info: Function defined here
   --> vgplot/plot.py:195:5
    |
195 | def vspace(px: int) -> Any:
    |     ^^^^^^ ------- Parameter declared here
    |

error[invalid-argument-type]: Argument to function `vspace` is incorrect
  --> /mosaic/docs/public/specs/python/legends.py:31:15
   |
31 |     vg.vspace("1em"),
   |               ^^^^^ Expected `int`, found `Literal["1em"]`
   |
info: Function defined here
   --> vgplot/plot.py:195:5
    |
195 | def vspace(px: int) -> Any:
    |     ^^^^^^ ------- Parameter declared here
    |

error[invalid-argument-type]: Argument to function `vspace` is incorrect
  --> /mosaic/docs/public/specs/python/legends.py:52:15
   |
52 |     vg.vspace("1em"),
   |               ^^^^^ Expected `int`, found `Literal["1em"]`
   |
info: Function defined here
   --> vgplot/plot.py:195:5
    |
195 | def vspace(px: int) -> Any:
    |     ^^^^^^ ------- Parameter declared here
    |

error[invalid-argument-type]: Argument to function `vspace` is incorrect
  --> /mosaic/docs/public/specs/python/legends.py:73:15
   |
73 |     vg.vspace("1em"),
   |               ^^^^^ Expected `int`, found `Literal["1em"]`
   |
info: Function defined here
   --> vgplot/plot.py:195:5
    |
195 | def vspace(px: int) -> Any:
    |     ^^^^^^ ------- Parameter declared here
    |

error[invalid-argument-type]: Argument to function `vspace` is incorrect
  --> /mosaic/docs/public/specs/python/protein-design.py:25:15
   |
25 |     vg.vspace("1.5em"),
   |               ^^^^^^^ Expected `int`, found `Literal["1.5em"]`
   |
info: Function defined here
   --> vgplot/plot.py:195:5
    |
195 | def vspace(px: int) -> Any:
    |     ^^^^^^ ------- Parameter declared here
    |

error[invalid-argument-type]: Argument to function `vspace` is incorrect
   --> /mosaic/docs/public/specs/python/protein-design.py:118:15
    |
118 |     vg.vspace("1em"),
    |               ^^^^^ Expected `int`, found `Literal["1em"]`
    |
info: Function defined here
   --> vgplot/plot.py:195:5
    |
195 | def vspace(px: int) -> Any:
    |     ^^^^^^ ------- Parameter declared here
    |

Found 7 diagnostics