bash-5.1 beta release

COMPAT

@@ -2,7 +2,7 @@ Compatibility with previous versions
 ====================================
 
 This document details the incompatibilities between this version of bash,
-bash-5.1, and the previous widely-available versions, bash-3.x (which is
+bash-5.1, and the previous widely-available versions, bash-3.2 (which is
 still the `standard' version for Mac OS X), 4.2/4.3 (which are still
 standard on a few Linux distributions), and bash-4.4/bash-5.0, the current
 widely-available versions.  These were discovered by users of bash-2.x
@@ -538,6 +538,11 @@ compat50 (set using BASH_COMPAT)
 	  lower, it reverts to the method from bash-5.0 and previous versions,
 	  so seeding the random number generator by assigning a value to
 	  RANDOM will produce the same sequence as in bash-5.0
+	- If the command hash table is empty, bash versions prior to bash-5.1
+	  printed an informational message to that effect even when writing
+	  output in a format that can be reused as input (-l). Bash-5.1
+	  suppresses that message if -l is supplied
+
 
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