message: feat(cli): improve wording of help text
diff: },
  {
  "flags": ["-r", "--reference"],
  - "desc": "Download dataset based on this reference sequence. Accession ID is used to specify the reference sequence. If not specified, will download dataset based on current default reference sequence, as defined by dataset maintainers. The default reference sequence can change over time. Use `dataset list` command to view available options.",
  + "desc": "Download dataset based on this reference sequence (given its accession ID). If this flag is not provided or is 'default', will download dataset based on current default reference sequence, as defined by dataset maintainers. The default reference sequence can change over time. Use `dataset list` command to view available options.",
  "cppName": "reference",
  "cppType": "std::string",
  "isOptional": true
  "options": [
  {
  "flags": ["-n", "--name"],
  - "desc": "List only datasets with this name.",
  + "desc": "Restrict list to only datasets with this name.",
  "cppName": "name",
  "cppType": "std::string",
  "isOptional": true
  },
  {
  "flags": ["-r", "--reference"],
  - "desc": "List only datasets based on this reference sequence. Accession ID is used to specify the reference sequence. Use `dataset list` command to view available options.",
  + "desc": "Restrict list to only datasets based on this reference sequence (given its accession ID)",
  "cppName": "reference",
  "cppType": "std::string",
  "isOptional": true
  },
  {
  "flags": ["-t", "--tag"],
  - "desc": "List only datasets with this version tag.",
  + "desc": "Restrict list to only datasets with this version tag.",
  "cppName": "tag",
  "cppType": "std::string",
  "isOptional": true
  },
  {
  "flags": ["--include-incompatible"],
  - "desc": "Include dataset version tags that are incompatible with this version of Nextclade CLI.",
  + "desc": "Include dataset version tags that are incompatible with this version of Nextclade CLI. By default the incompatible versions are omitted.",
  "cppName": "includeIncompatible",
  "cppType": "bool",
  "defaultValue": "false",
  },
  {
  "flags": ["--include-old"],
  - "desc": "Include older dataset version tags, additional to the latest.",
  + "desc": "Include older dataset version tags, additional to the latest. By default the old versions are omitted.",
  "cppName": "includeOld",
  "cppType": "bool",
  "defaultValue": "false",
  