readme: small wording improvements (#610)

Removes an extra `the` in the Readme about the tested Linux versions

README.md

@@ -368,7 +368,7 @@ The application can be compiled for macOS. A user reported, that the library wor
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-Unfortunately, there is no such thing as a Linux operating system. Linux is a heterogeneous environment with a variety of different distributions. So it is not possible to support "Linux" like this is possible for Windows. It is only possible to support and test a small subset of Linux distributions. The library can be compiled for and has been developed and tested with the some Linux distributions. Depending on the used window manager or compositor, dock widgets
+Unfortunately, there is no such thing as a Linux operating system. Linux is a heterogeneous environment with a variety of different distributions. So it is not possible to support "Linux" like it is possible for Windows. It is only possible to support and test a small subset of Linux distributions. The library can be compiled for and has been developed and tested with some Linux distributions. Depending on the used window manager or compositor, dock widgets
 with native title bars are supported or not. If native title bars are not supported,
 the library switches to `QWidget` based title bars.