message: doc: fix in training
diff: @@ -70,14 +70,13 @@ multi-channel EXR image files are not supported. If you have multi-channel EXRs,
  you can split them into separate images per feature using the included
  `split_exr.py` tool.
  -An image filename must consist of a name (any valid filename character except
  -`_` is allowed), the number of samples per pixel or whether it is the reference
  -(e.g. `0128spp`, `ref`), the identifier (ID) of the feature (e.g. `hdr`, `alb`),
  -and the file extension (`.exr`). This format as a regular expression is the
  -following:
  +An image filename must consist of a name, the number of samples per pixel or
  +whether it is the reference (e.g. `0128spp`, `ref`), the identifier (ID) of the
  +feature (e.g. `hdr`, `alb`), and the file extension (`.exr`). The exact format
  +as a regular expression is the following:
  ```regexp
  -[^_]+_([0-9]+(spp)?|ref|reference|gt|target)\.(hdr|ldr|alb|nrm)\.exr
  +.+_([0-9]+(spp)?|ref|reference|gt|target)\.(hdr|ldr|alb|nrm)\.exr
  ```
  The number of samples per pixel should be padded with leading zeros to have a
  