ENH: fix docs to include linker lang

Source/cmSetTargetPropertiesCommand.h

@@ -94,6 +94,11 @@ public:
         "to build sources within the target.  It may also be used to pass "
         "additional preprocessor definitions."
         "\n"
+        "The LINKER_LANGUAGE property is used to change the tool "
+        "used to link an executable or shared library. The default is "
+        "set the language to match the files in the library. CXX and C "
+        "are common values for this property."
+        "\n"
         "For shared libraries VERSION and SOVERSION can be used to specify "
         "the build version and api version respectively. When building or "
         "installing appropriate symlinks are created if the platform "