Revamp the USING clause processing so that it works (mostly) with RIGHT

and FULL JOIN.

FossilOrigin-Name: 719c8d920b435b0f234d47467a2abe2941ab7d55ecca886e211cfce577ae648c

diff --cc manifest
index fc69bf60d059b5abfb530c117e75a24654b2835c,f16f6e95642ce445cad4297b588927541724715c..fed1873bb694734e3da1c3e612c8dd6cc2cee5bf
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C The\ssqlite3ProcessJoin()\sroutine\sconverts\sa\sNATURAL\sJOIN\sinto\sa\sJOIN\sUSING\sso\nthat\shenceforth\sthe\sNATURAL\skeyword\scan\sbe\signored.
- D 2022-04-15T17:08:40.527
 -C Avoid\sdeleting\ssubstructure\sof\sthe\sExpr\snode\sin\slookupName()\suntil\safter\nthe\serror\smessage\sis\sgenerated.
 -D 2022-04-15T19:49:28.612
++C Revamp\sthe\sUSING\sclause\sprocessing\sso\sthat\sit\sworks\s(mostly)\swith\sRIGHT\nand\sFULL\sJOIN.
++D 2022-04-15T19:53:35.253
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -1947,8 -1947,8 +1947,9 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P 40f3c95871e6f40f287ef2756abafb8fc56dffdd0af69436e5c7d8e95022d94e
- R a4dbe6f876199f457625a48f56e40a96
 -P fed2646adecb0a05dd674dc1cd2c0ae205078fe552ba93b8d68891c728c67637
++P 8378e1e0d289627fb294ccd3f5865ef49df3a42b8a5aa211e21be1b42d9da753 b8e717663957dfd84e580bf21bc8e8881b33fdb94a2cc0c664a230e54d5e5076
+ R 1c50cd468ee936498b2b4c9dc93da894
++T +closed b8e717663957dfd84e580bf21bc8e8881b33fdb94a2cc0c664a230e54d5e5076
  U drh
- Z 67a6ae70c20850bccd3ed1b730f595c0
 -Z f18fddb58ed361d0fe042b1d1d670157
++Z e84867876e1dda583c8d47e448336a7d
  # Remove this line to create a well-formed Fossil manifest.

diff --cc manifest.uuid
index a6a28508708e1ab731c713759b906c73b895c90a,130732878ab17647e0fb727d804470435df45409..2a8e66f8f7046c373ea7c3f25610fd3e772e318c
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 8378e1e0d289627fb294ccd3f5865ef49df3a42b8a5aa211e21be1b42d9da753
 -b8e717663957dfd84e580bf21bc8e8881b33fdb94a2cc0c664a230e54d5e5076
++719c8d920b435b0f234d47467a2abe2941ab7d55ecca886e211cfce577ae648c