Create docs for from-csv command

Partial fix of issue nushell#711

docs/commands/from-csv.md

@@ -0,0 +1,47 @@
+# from-csv
+
+Converts csv data into table. Use this when nushell cannot dertermine the input file extension.
+
+## Example
+Let's say we have the following file :
+```shell
+> cat pets.txt
+animal, name, age
+cat, Tom, 7
+dog, Alfred, 10
+chameleon, Linda, 1
+```
+
+`pets.txt` is actually a .csv file but it has the .txt extension, `open` is not able to convert it into a table :
+
+```shell
+> open pets.txt
+animal, name, age
+cat, Tom, 7
+dog, Alfred, 10
+chameleon, Linda, 1
+```
+
+To get a table from `pets.txt` we need to use the `from-csv` command :
+
+```shell
+> open pets.txt | from-csv
+━━━┯━━━━━━━━━━━┯━━━━━━━━━┯━━━━━━
+ # │ animal    │  name   │  age
+───┼───────────┼─────────┼──────
+ 0 │ cat       │  Tom    │  7
+ 1 │ dog       │  Alfred │  10
+ 2 │ chameleon │  Linda  │  1
+━━━┷━━━━━━━━━━━┷━━━━━━━━━┷━━━━━━
+```
+
+To ignore the csv headers use `--headerless` :
+```shell
+━━━┯━━━━━━━━━━━┯━━━━━━━━━┯━━━━━━━━━
+ # │ Column1   │ Column2 │ Column3
+───┼───────────┼─────────┼─────────
+ 0 │ dog       │  Alfred │  10
+ 1 │ chameleon │  Linda  │  1
+━━━┷━━━━━━━━━━━┷━━━━━━━━━┷━━━━━━━━━
+```
+