qt module: fix error message typo, translation qresource accepts qm not ts

Fixes #7925

docs/markdown/Qt5-module.md

@@ -79,7 +79,8 @@ executable('myprog', 'main.cpp', 'myclass.cpp', moc_files,
 ```
 
 Sometimes, translations are embedded inside the binary using qresource files.
-In this case the ts files do not need to be explicitly listed. For example:
+In this case the ts files do not need to be explicitly listed, but will be
+inferred from the built qm files listed in the qresource file. For example:
 
 ```meson
 qt5 = import('qt5')

mesonbuild/modules/qt.py

@@ -236,7 +236,7 @@ class QtBaseModule(ExtensionModule):
                 if c.endswith('.qm'):
                     ts_files.append(c.rstrip('.qm')+'.ts')
                 else:
-                    raise MesonException('qt.compile_translations: qresource can only contain ts files, found {}'.format(c))
+                    raise MesonException('qt.compile_translations: qresource can only contain qm files, found {}'.format(c))
             results = self.preprocess(state, [], {'qresources': qresource, 'rcc_extra_arguments': kwargs.get('rcc_extra_arguments', [])})
         self._detect_tools(state.environment, kwargs.get('method', 'auto'))
         translations = []