Merge the query flattener comment improvements from trunk.

FossilOrigin-Name: f62cd4d940506c39db82e83ff3df8ab1856f1fb91ffda835ae2d727263ee9b0b

diff --cc manifest
index 839e47c4527b311dbd8fded6c4a3e94f655cc157,87b5990a98ed2221cc1b059321c03e6e52847267..26986bd8f35b798527b519a9a5e8c653d3f478ef
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Merge\schanges\sfrom\strunk.
- D 2017-09-29T14:31:16.862
 -C Clean\sup\sthe\scomments\son\sthe\squery\sflattener\sto\smore\sclearly\sand\saccurately\nexpress\sthe\sconditions\sunder\swhich\sthe\sflattener\sis\sable\sto\srun.
 -D 2017-09-29T16:07:56.167
++C Merge\sthe\squery\sflattener\scomment\simprovements\sfrom\strunk.
++D 2017-09-29T16:08:46.956
  F Makefile.in 4bc36d913c2e3e2d326d588d72f618ac9788b2fd4b7efda61102611a6495c3ff
  F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
  F Makefile.msc 6033b51b6aea702ea059f6ab2d47b1d3cef648695f787247dd4fb395fe60673f
@@@ -458,7 -458,7 +458,7 @@@ F src/printf.c 40aee47ae9be4bd3dbdc8968
  F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
  F src/resolve.c 4324a94573b1e29286f8121e4881db59eaedc014afeb274c8d3e07ed282e0e20
  F src/rowset.c 7b7e7e479212e65b723bf40128c7b36dc5afdfac
- F src/select.c 117cbceca91e71956092afe064a32de6f8b73096c669a250a673bb5b9bed4c77
 -F src/select.c 733e7f727d4f83234983fcbcb71670229f6d9ae78ee724fbf40b4aa6904474e2
++F src/select.c 73fa1cc03a325dd5f3e84bc6c4c975000028f96f85025ae2fe0b6eb0c30c2fe0
  F src/shell.c c1206a23d9239f8f51751d3be9b8c3b02fa4103546bea1add7f864d84a8276ab
  F src/shell.c.in bb9720a8c5c98d3984b16ab7540e7142bcae959666ecf248bfc523a1d44220ee
  F src/sqlite.h.in ab4f8a29d1580dfaeb6891fa1b83cff8229ba0daa56994707ceaca71495d9ab7
@@@ -1655,7 -1655,7 +1655,7 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P 042d655dd9002e8b89a798ad955b0285891aecf79f6978c5312e70ffe0609a46 2a45bbc9fd1c64f1c4c4dac38f063cd67480fcb6da24bf93fdefbfca66fd81ab
- R 635e2ef6a6d5adad412e10e82845888b
 -P 2a45bbc9fd1c64f1c4c4dac38f063cd67480fcb6da24bf93fdefbfca66fd81ab
 -R 5dd9d1abad7c6b3045de562026df2e52
++P 06f432fb7c979f1bb7f01f5c90716ce5c0248f73f70b78a9870b9de5c9bf7ef4 0840f9f824c16212ce3fd6c859e501176eb0a58924ea1728a54d5bdfd0c25c86
++R 4be3453c15fd85db566735e226eb00f9
  U drh
- Z 2ad1dca5cd127635056074671b5ec8b9
 -Z 40508487cfccebe9fe70dcdbc46f56d0
++Z be149bf809ee0d7792ea4e04a36ef7f0

diff --cc manifest.uuid
index b63e737bcd8b38c74c50b4f3d86f79850fb56638,48e1728350c5ac17e8743c6d30326a00d3c33130..bef919b1e85fa3f564772a3ddb6f85ce97adc05e
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 06f432fb7c979f1bb7f01f5c90716ce5c0248f73f70b78a9870b9de5c9bf7ef4
 -0840f9f824c16212ce3fd6c859e501176eb0a58924ea1728a54d5bdfd0c25c86
++f62cd4d940506c39db82e83ff3df8ab1856f1fb91ffda835ae2d727263ee9b0b

diff --cc src/select.c
Simple merge