UI: Fix and improve a few messages

UI: Fix and improve a few messages

- "Log Encoding with Chroma inset and rotation": add "of primaries" in
  the description of the AgX Log color space to better explain the
  operation, based on wording in !106355.
- Remove a few double spaces.
- Make Line Art title case everywhere, to convey it's the system /
  brand / product name and not the generic concept.
- "Copy Absolute coordinates or Normal vector" -> "of Normal Vector":
typo.
- "Makes a link between selected output in input sockets" ->
  "Make...", "output and input": typo.
- "Purge Unused Data From This File" -> "from this": title case as per
  HIGs.
- GPencil -> Grease Pencil: no reason to use an abbreviation here.
- "Around Current Frame" -> "Around Frame": actual name of the
  onion-skinning method.
- "... (layer height for layer tool, i.e.)" -> "(i.e. the layer height
  for the layer tool)": put "i.e." at the start of the sentence.
- Expand description of toe-in stereo camera option.
- "Children collections their parent-collection-specific settings" ->
  "Children collections with their...": typo.
- "Generate vertex weights base on..." -> "based on" : typo, lower
  case.
- Expand description of GP modifier properties, based on their mesh
  counterparts.
- "AEnvelope" -> "Envelope": typo.
- "Falloff type the feather" -> "of the feather": typo.
- "usually make transition as long as effect strip": rephrase.
- "When disabled a users extensions directory is created" -> "a
  user's": typo.
- "successfull" -> "successful": typo.
- "Remove all attributes... a single wildcard (*).": remove trailing
  ".".
- "..., use "Save Preferences."": remove trailing ".".

Some issues reported by Marina Veselkova and Tamar Mebonia.

Pull Request: https://projects.blender.org/blender/blender/pulls/120649