Datasheet path resolution issue with double slashes
# Description
In the Schematic Editor hovering a symbol and pressing "D" key should open the datasheet document corrsponding to the field "Datasheet" of that symbol.
If the field contains a hyperlink (web) the page opens and the pdf document is displayed correctly.
If the field contains a local path to a pdf file, the following error message is displayed:
The System default PDF viewer option is selected in the Preferences as shown:
Changing this option to "Other:" to point to the binary of the system PDF viewer (Foxit PDF Reader) fixes the issue and the PDF opens as expected:
The issue seems to be related to KiCAD not being able to find the system's default PDF viewer.
# KiCad Version
```
Application: KiCad Schematic Editor x64 on x64
Version: 7.0.2, release build
Libraries:
wxWidgets 3.2.2
FreeType 2.12.1
HarfBuzz 6.0.0
FontConfig 2.14.1
libcurl/7.88.1-DEV Schannel zlib/1.2.13
Platform: Windows 11 (build 25300), 64-bit edition, 64 bit, Little endian, wxMSW
Build Info:
Date: Apr 15 2023 19:18:27
wxWidgets: 3.2.2 (wchar_t,wx containers)
Boost: 1.81.0
OCC: 7.6.3
Curl: 7.88.1-DEV
ngspice: 40
Compiler: Visual C++ 1934 without C++ ABI
Build settings:
KICAD_SPICE=ON
```
issue