Add support for the RETURNING clause following PostgreSQL syntax.

FossilOrigin-Name: 416c898bfb8ff9639ffbaefcfb47fce3782763af1fc67969fa91c5f01a336676

diff --cc manifest
index 397bdd967819b4ea81d01724e1c28661ece7019f,8950ada11e97f30d044ca1b7911483206cae460d..b8b3e0e883f6365d2e0ad604426b6a393ac2970b
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Fix\san\sassert()\sthat\smight\sbe\soff-by-one\sin\sthe\scase\sof\sa\sprior\nerrors\sin\sthe\sparse.
- D 2021-02-03T12:35:51.366
 -C Modify\sthe\sSQLITE_DBCONFIG_ENABLE_TRIGGER\ssetting\sso\sthat\sit\sonly\sdisables\nmain-schema\striggers\sand\sallows\sTEMP\strigger\sto\scontinue\soperating.\s\sThis\sis\nsafe,\ssince\sonly\sthe\sapplication\s(not\san\sattacker)\scan\sadd\sTEMP\striggers.\nIt\swill\salso\sall\sus\sto\sdisengage\sSQLITE_DBCONFIG_ENABLE_TRIGGER\son\sFossil\ndatabases\ssince\sFossil\shas\sno\smain-schema\striggers\sbut\sdoes\suse\sTEMP\striggers.
 -D 2021-02-03T00:55:34.680
++C Add\ssupport\sfor\sthe\sRETURNING\sclause\sfollowing\sPostgreSQL\ssyntax.
++D 2021-02-03T13:08:09.152
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -1898,7 -1899,7 +1899,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
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  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
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  U drh
- Z 17a66c8e0166569653feae3b32e8dbae
 -Z cfd272038413f78f81e2c24e00e99d6f
++Z 40f463993ad19f6f3483715fa2a6abfe

diff --cc manifest.uuid
index 7cec0847e34ba0b7cabc39515dca15d25bb053dc,e1651727c4232318fd914f5e5af0b5faa53bbccf..d25c8a154489d1f9ec697d765a434f775457b947
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 06b15b17be38c804dd2641d8616a2a7bd396d2eb9901a0fbf94edd8bd508cf9c
 -a10c5a2503ff2998f6ee40f721aab8c9579052e535dc141bd57d10551eaea387
++416c898bfb8ff9639ffbaefcfb47fce3782763af1fc67969fa91c5f01a336676