Elaborate on the open-in-read-only fallback behavior of the SQLITE_OPEN_READWRITE flag, per user request. Unrelated trailing EOL whitespace cleanups.

FossilOrigin-Name: 1003144fc192e1531e1bc968d7e1d0ccc7ad31e501180f90e1479565a4abfb96

manifest

@@ -1,5 +1,5 @@
-C Remove\sthe\sJS-side\sSQLITE_WASM_DEALLOC\ssanity\scheck\swhich\striggers\sthe\sproblem\smentioned\sin\s[688c5c13d156]\sand\s[ae0196d86ee8],\sfor\sreasons\scovered\sin\sthe\scode\scomments,\sper\sdiscussion\sin\s[forum:e5b20e1feb|forum\spost\se5b20e1feb].
-D 2023-01-04T03:14:06.615
+C Elaborate\son\sthe\sopen-in-read-only\sfallback\sbehavior\sof\sthe\sSQLITE_OPEN_READWRITE\sflag,\sper\suser\srequest.\sUnrelated\strailing\sEOL\swhitespace\scleanups.
+D 2023-01-04T11:57:27.127
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -647,7 +647,7 @@ F src/resolve.c efea4e5fbecfd6d0a9071b0be0d952620991673391b6ffaaf4c277b0bb674633
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
 F src/select.c 83de67e4857be2866d048c98e93f65461d8a0408ca4ce88fec68ebfe030997ae
 F src/shell.c.in 01816a1e0eb3a2e9a9a4b11570d68058969c88b2ec5ecaf80c57d6ca1b8d46a4
-F src/sqlite.h.in 7982c691e4647071a6df1ef45e7d704613225259414e153939b0928a9952a1ae
+F src/sqlite.h.in 973f6b2e9a6599b14eec6f88212d83a1d4e888bf62086e46b0580614f78cea7c
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h c4b9fa7a7e2bcdf850cfeb4b8a91d5ec47b7a00033bc996fd2ee96cbf2741f5f
 F src/sqliteInt.h e0c0fdb6a475c8dcf94c48bc0521c7381ae28239ce9a23d8fbfdea249c0d2899
@@ -2067,8 +2067,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a19597b4fd2530a89363992b9179f9f3f0621a6e3861a91324f29311aafe09b9
-R cf7736aed38ba8edc7ed369b784dbcd1
+P 65ff3200c6009a1649fc108d7ce36f5c014185ba46bbf98471ec86eaeb572656
+R ff536d5b4bd68ee026a95d2a22179954
 U stephan
-Z 0d48cca09eb0bd8b01ad4e4900dbb440
+Z 24f9760adb78b1f8854f3748c7f5f544
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-65ff3200c6009a1649fc108d7ce36f5c014185ba46bbf98471ec86eaeb572656
+1003144fc192e1531e1bc968d7e1d0ccc7ad31e501180f90e1479565a4abfb96

src/sqlite.h.in

@@ -3423,13 +3423,18 @@ void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
 **
 ** <dl>
 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
-** <dd>The database is opened in read-only mode.  If the database does not
-** already exist, an error is returned.</dd>)^
+** <dd>The database is opened in read-only mode.  If the database does
+** not already exist, an error is returned.</dd>)^
 **
 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
-** <dd>The database is opened for reading and writing if possible, or reading
-** only if the file is write protected by the operating system.  In either
-** case the database must already exist, otherwise an error is returned.</dd>)^
+** <dd>The database is opened for reading and writing if possible, or
+** reading only if the file is write protected by the operating
+** system.  In either case the database must already exist, otherwise
+** an error is returned.  For historical reasons, if opening in
+** read-write mode fails due to OS-level permissions, an attempt is
+** made to open it in read-only mode. [sqlite3_db_readonly()] can be
+** used to determine whether the database is actually
+** read-write.</dd>)^
 **
 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
 ** <dd>The database is opened for reading and writing, and is created if