🐛 Fix off-by-one in API "View code" source links

`@deno/doc` v2 changed `Location.line` from 1-indexed to 0-indexed (deno_doc
#150/#777). GitHub's `#L<n>` anchor is 1-indexed, so the source links generated
in package.ts / package/node.ts pointed one line above the symbol's
declaration. Add `+ 1`.

Author: taras

www/lib/package.ts

@@ -178,7 +178,7 @@ function* initPackage(
                         path,
                         fileURLToPath(section.declaration.location.filename),
                       )
-                    }#L${section.declaration.location.line}`,
+                    }#L${section.declaration.location.line + 1}`,
                     `${ref.url}/`,
                   ),
                 },

www/lib/package/node.ts

@@ -268,7 +268,7 @@ export function createNodePackage(
                       path,
                       fileURLToPath(section.declaration.location.filename),
                     )
-                  }#L${section.declaration.location.line}`,
+                  }#L${section.declaration.location.line + 1}`,
                   `${ref.url}/`,
                 ),
               },