Use a ("""-formatted) docstring for our R script to dump variables in .rdb files.

diffoscope/comparators/rdata.py

@@ -32,10 +32,13 @@ import binascii
 
 HEADER = binascii.a2b_hex("580a000000020003")
 
-# has to be one line
-DUMP_RDB = """lazyLoad(commandArgs(TRUE)); for (obj in ls()) { print(obj); for (line in deparse(get(obj))) cat(line,"\\n"); }"""
-# unfortunately this above snippet can't detect the build-path differences so
-# diffoscope still falls back to a hexdump
+DUMP_RDB = r"""
+lazyLoad(commandArgs(TRUE));
+for (obj in ls()) {
+    print(obj);
+    for (line in deparse(get(obj)))
+        cat(line,"\n");
+}"""
 
 logger = logging.getLogger(__name__)