Docs: Cleaned redundant unit mapping in TYPE_CONVERSION dictionary for clarity

Author: Akhila21-6

conversions/length_conversion.py

@@ -36,7 +36,6 @@ class FromTo(NamedTuple):
     "meter": "m",
     "kilometer": "km",
     "inch": "in",
-    "inche": "in",  # Trailing 's' has been stripped off
     "feet": "ft",
     "foot": "ft",
     "yard": "yd",