doxygen: doxygen.groups changed again to groups.md due to doxygen limitations

Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

docs/documentation.md

@@ -66,7 +66,7 @@ Here's an example (disregard the "@verbatim" tags in your actual code):
 - `<component-kit>` Specifies if the sensor is part of a kit. *Optional*
 
 Existing groups that can be used for the manufacturer, connection, category and
-kit tags are found in the *src/doxygen.groups* file.
+kit tags are found in the *src/groups.md* file.
 
 Optionally, a small representative image can be placed in the "docs/images"
 subfolder and linked with the "@image" tag.

doxy/Doxyfile.in

@@ -764,7 +764,7 @@ WARN_LOGFILE           =
 # spaces.
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = @CMAKE_CURRENT_SOURCE_DIR@/src/doxygen.groups \
+INPUT                  = @CMAKE_CURRENT_SOURCE_DIR@/src/groups.md \
                          @CMAKE_CURRENT_SOURCE_DIR@/src \
                          @CMAKE_CURRENT_SOURCE_DIR@/docs \
                          @CMAKE_CURRENT_SOURCE_DIR@/doxy/README.cpp.md

doxy/Doxyfile.java.in

@@ -764,7 +764,7 @@ WARN_LOGFILE           =
 # spaces.
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = @CMAKE_CURRENT_SOURCE_DIR@/src/doxygen.groups \
+INPUT                  = @CMAKE_CURRENT_SOURCE_DIR@/src/groups.md \
                          @CMAKE_BINARY_DIR@/src \
                          @CMAKE_CURRENT_SOURCE_DIR@/docs \
                          @CMAKE_CURRENT_SOURCE_DIR@/doxy/README.java.md