Port before_v0.60/math, before_v0.60/parsing and before_v0.60/git (nushell#844)

This PR is part of porting all old scripts nushell#221 and includes a set of
small modules:
- `math`
- `parsing`
- `git`

Author: 39555

before_v0.60/git/git_branch_cleanup.nu

@@ -1,13 +1,13 @@
 # Creates a table listing the branches of a git repository and the day of the last commit
-def "git age" [] {
+export def "git age" [] {
     git branch |
     lines |
-    str substring 2, |
+    str substring 2.. |
     wrap name |
     insert last_commit {
         get name |
         each {
-            git show $it --no-patch --format=%as | str to-datetime
+            git show $in --no-patch --format=%as | into datetime
         }
     } |
     sort-by last_commit

before_v0.60/maths/math_functions.nu

@@ -5,17 +5,17 @@ def look_for [word] {
     insert comp {
         get shoes_name |
             split row " " |
-            each --numbered {
-        [[idx, loc]; [$it.index, ($it.item | str index-of $word)]]
-        }
+            enumerate | each {
+        [[idx, loc]; [$in.index, ($in.item | str index-of $word)]]
+        } | flatten
     } |
     flatten |
     where comp.loc >= 0 |
     flatten |
-    update idx { $it.idx + 1 } |
+    update idx { $in + 1 } |
     reject name price loc |
     rename nameWords targetWordIndex
 }
 
-look_for "leather" | to json --pretty 4
-look_for "low-top" | to json --pretty 4
+print (look_for "leather" | to json --indent 4)
+print (look_for "low-top" | to json --indent 4)