doc: fix broken references

There are numerous broken references to Documentation files (in other
Documentation files, in comments, etc.). These broken references are
caused by typo's in the references, and by renames or removals of the
Documentation files. Some broken references are simply odd.

Fix these broken references, sometimes by dropping the irrelevant text
they were part of.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index fe02903..80d9598 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -341,7 +341,7 @@
 
 static int perf_default_core_config(const char *var __used, const char *value __used)
 {
-	/* Add other config variables here and to Documentation/config.txt. */
+	/* Add other config variables here. */
 	return 0;
 }
 
@@ -350,7 +350,7 @@
 	if (!prefixcmp(var, "core."))
 		return perf_default_core_config(var, value);
 
-	/* Add other config variables here and to Documentation/config.txt. */
+	/* Add other config variables here. */
 	return 0;
 }