Implement Pandoc Markdown concise link extension (#20304)

* Implement Pandoc Markdown concise link extension

This implements https://github.com/nim-lang/Nim/issues/20127.
Besides reference to headings we also support doing references
to Nim symbols inside Nim modules.

Markdown:
```
Some heading
------------

Ref. [Some heading].
```

Nim:
```
proc someFunction*() ...

... ## Ref. [someFunction]
```

This is substitution for RST syntax like `` `target`_ ``.
All 3 syntax variants of extension from Pandoc Markdown are supported:
`[target]`, `[target][]`, `[description][target]`.

This PR also fixes clashes in existing files, particularly
conflicts with RST footnote feature, which does not work with
this PR (but there is a plan to adopt a popular [Markdown footnote
extension](https://pandoc.org/MANUAL.html#footnotes) to make footnotes work).

Also the PR fixes a bug that Markdown links did not work when `[...]`
section had a line break.

The implementation is straightforward since link resolution did not
change w.r.t. RST implementation, it's almost only about new syntax
addition. The only essential difference is a possibility to add a custom
link description: form `[description][target]` which does not have an
RST equivalent.

* fix nim 1.0 gotcha

3 files changed, 7 insertions, 7 deletions

diff --git a/lib/impure/db_mysql.nim b/lib/impure/db_mysql.nim
index 87fd34913..9a98cb9c5 100644
--- a/lib/impure/db_mysql.nim
+++ b/lib/impure/db_mysql.nim
@@ -180,7 +180,7 @@ iterator fastRows*(db: DbConn, query: SqlQuery,
   ## if you require **ALL** the rows.
   ##
   ## Breaking the fastRows() iterator during a loop will cause the next
-  ## database query to raise an [EDb] exception `Commands out of sync`.
+  ## database query to raise an `EDb` exception `Commands out of sync`.
   rawExec(db, query, args)
   var sqlres = mysql.useResult(PMySQL db)
   if sqlres != nil:
@@ -203,7 +203,7 @@ iterator instantRows*(db: DbConn, query: SqlQuery,
                       args: varargs[string, `$`]): InstantRow
                       {.tags: [ReadDbEffect].} =
   ## Same as fastRows but returns a handle that can be used to get column text
-  ## on demand using []. Returned handle is valid only within the iterator body.
+  ## on demand using `[]`. Returned handle is valid only within the iterator body.
   rawExec(db, query, args)
   var sqlres = mysql.useResult(PMySQL db)
   if sqlres != nil:
@@ -283,7 +283,7 @@ proc setColumnInfo(columns: var DbColumns; res: PRES; L: int) =
 iterator instantRows*(db: DbConn; columns: var DbColumns; query: SqlQuery;
                       args: varargs[string, `$`]): InstantRow =
   ## Same as fastRows but returns a handle that can be used to get column text
-  ## on demand using []. Returned handle is valid only within the iterator body.
+  ## on demand using `[]`. Returned handle is valid only within the iterator body.
   rawExec(db, query, args)
   var sqlres = mysql.useResult(PMySQL db)
   if sqlres != nil:
diff --git a/lib/impure/db_odbc.nim b/lib/impure/db_odbc.nim
index 0ecd8129f..da1b1e9b5 100644
--- a/lib/impure/db_odbc.nim
+++ b/lib/impure/db_odbc.nim
@@ -168,7 +168,7 @@ proc dbError*(db: var DbConn) {.
     raise e
 
 proc sqlCheck(db: var DbConn, resVal: TSqlSmallInt) {.raises: [DbError]} =
-  ## Wrapper that raises [EDb] if `resVal` is neither SQL_SUCCESS or SQL_NO_DATA
+  ## Wrapper that raises `EDb` if `resVal` is neither SQL_SUCCESS or SQL_NO_DATA
   if resVal notIn [SQL_SUCCESS, SQL_NO_DATA]: dbError(db)
 
 proc sqlGetDBMS(db: var DbConn): string {.
@@ -304,7 +304,7 @@ iterator instantRows*(db: var DbConn, query: SqlQuery,
                       args: varargs[string, `$`]): InstantRow
                 {.tags: [ReadDbEffect, WriteDbEffect].} =
   ## Same as fastRows but returns a handle that can be used to get column text
-  ## on demand using []. Returned handle is valid only within the iterator body.
+  ## on demand using `[]`. Returned handle is valid only within the iterator body.
   var
     rowRes: Row = @[]
     sz: TSqlLen = 0
diff --git a/lib/impure/db_postgres.nim b/lib/impure/db_postgres.nim
index 82403ab00..e629b7945 100644
--- a/lib/impure/db_postgres.nim
+++ b/lib/impure/db_postgres.nim
@@ -271,7 +271,7 @@ iterator instantRows*(db: DbConn, query: SqlQuery,
                       args: varargs[string, `$`]): InstantRow
                       {.tags: [ReadDbEffect].} =
   ## same as fastRows but returns a handle that can be used to get column text
-  ## on demand using []. Returned handle is valid only within iterator body.
+  ## on demand using `[]`. Returned handle is valid only within iterator body.
   setupSingeRowQuery(db, query, args)
   fetchinstantRows(db)
 
@@ -279,7 +279,7 @@ iterator instantRows*(db: DbConn, stmtName: SqlPrepared,
                       args: varargs[string, `$`]): InstantRow
                       {.tags: [ReadDbEffect].} =
   ## same as fastRows but returns a handle that can be used to get column text
-  ## on demand using []. Returned handle is valid only within iterator body.
+  ## on demand using `[]`. Returned handle is valid only within iterator body.
   setupSingeRowQuery(db, stmtName, args)
   fetchinstantRows(db)