Error: (vsim-3170) Could not find 'wordmatch_simtop_tc'

When running the vhdeps script in the wikipedia search demo, questasim is unable to locate the testbench.

```
# ** Error: (vsim-3170) Could not find 'wordmatch_simtop_tc'.
# Searched libraries:
# /tmp/tmpkgw0_t6s/unisim
# Error loading design
```

To reproduce:
```
git clone https://github.com/joosthooz/wiki-search-alveo.git
cd wiki-search-alveo/hardware
./run-vhdeps.sh vsim work.WordMatch_SimTop_tc
```

Jeroen and I found a workaround:
```
./run-vhdeps.sh vsim work:WordMatch_SimTop_tc
```

The `run-vhdeps.sh` script is:
```
vhdeps "$@" -i vhdl -i fletcher/hardware -i tta_rtl -i tta_support_rtl -x unisim:$XILINX_VIVADO/data/vhdl/src/unisims/unisim_VCOMP.vhd
```

The issue is in the run-vhdeps.sh script, which passes arguments to the vhdeps tool. Compare the failing command 'work.WordMatch_SimTop_tc' with the working 'work:WordMatch_SimTop_tc'. Look at how vhdeps parses its command-line arguments and handles library/entity separators. Check the vhdeps source code for argument parsing logic, and see if the separator (dot vs colon) is misinterpreted. Running the provided reproduction steps will show the error.

索引モデルが issue の本文から書いたものです。