Add a comment with useful information about SHM locking. No changes to

deliverable code.

FossilOrigin-Name: 4e81ea3b15fb3fce5f31b77273639e748a735ab0970620e564e9a5c977b24a1a

diff --cc manifest
index 0aa7c7bbf49c21551643c558999eab6b5388195a,7f07f63dff958e9012eb23b5d3d011c87d6e9991..cf9dcdfb7141f17e5cfe30fa3d0f8bf0fc431e79
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Allow\saggregate\ssub-selects\swithin\sORDER\sBY\sand\sPARTITION\sBY\sclauses\sof\swindow\sframe\sdefinitions.
- D 2021-05-19T14:49:51.085
 -C Fix\sa\sformatting\serror\son\sthe\scomment.
 -D 2021-05-19T19:27:42.183
++C Add\sa\scomment\swith\suseful\sinformation\sabout\sSHM\slocking.\s\sNo\schanges\sto\ndeliverable\scode.
++D 2021-05-19T19:28:48.372
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -1913,7 -1913,7 +1913,7 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P 699c33990a9438f28673ecf34f1e521d1af0b01c6ee30a608c0c91d2d593590e
- R 0588b9cafca27fd37e2a788a361f330d
- U dan
- Z 63f7d84596bbfc34c19eb092e10320fc
 -P b480aacb3430a789d98ffd81a1886bbbc3cda5b0e736ec9a3e2b463db2a3b3ad
++P 3daab94977af5e8a95690acc555540311403d890a3261a9757c633fcaaf428a9 6f2fb60e499fc758bea6ffec030fef8ab5f97d08d31450f0b3ffafc20e652891
+ R 51a5c10eeb74e980a28bc317ddd05223
+ U drh
 -Z 312f630c2639a44670ce7c2d40505de2
++Z b7fe08aae0b2fc89ef00be04a5d5c5af

diff --cc manifest.uuid
index cead1d48d872077c11f58df163499e79cdc05685,eba0a762d52163423bd501d9c497571c6f60f02b..ad72fd93f79d1b2b131992842db46567c29e95f3
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 3daab94977af5e8a95690acc555540311403d890a3261a9757c633fcaaf428a9
 -6f2fb60e499fc758bea6ffec030fef8ab5f97d08d31450f0b3ffafc20e652891
++4e81ea3b15fb3fce5f31b77273639e748a735ab0970620e564e9a5c977b24a1a