add completions to gm repo fetch branch (#138)

as per title

docs/nu-git-manager-sugar/git/gm-repo-fetch-branch.md

@@ -6,21 +6,24 @@ fetch a remote branch locally, without pulling down the whole remote
 ## Parameters
 - parameter_name: remote
 - parameter_type: positional
-- syntax_shape: string
+- syntax_shape: completable<string>
 - is_optional: false
 - description: the branch to fetch
+- custom_completion: get-remotes
 ---
 - parameter_name: branch
 - parameter_type: positional
-- syntax_shape: string
+- syntax_shape: completable<string>
 - is_optional: false
 - description: the remote to fetch the branch from
+- custom_completion: get-branches
 ---
 - parameter_name: strategy
 - parameter_type: named
-- syntax_shape: string
+- syntax_shape: completable<string>
 - is_optional: true
 - description: the merge strategy to use
+- custom_completion: get-strategies
 - parameter_default: none
 
 ## Signatures

src/nu-git-manager-sugar/completions/nu-complete.nu

@@ -3,3 +3,17 @@ export const GIT_QUERY_TABLES = ["refs", "commits", "diffs", "branches", "tags"]
 export def git-query-tables []: nothing -> list<string> {
     $GIT_QUERY_TABLES
 }
+
+export const GIT_STRATEGIES = ["merge", "rebase", "none"]
+
+export def get-remotes []: nothing -> list<string> {
+    ^git remote --verbose show | lines | parse "{remote}\t{rest}" | get remote | uniq
+}
+
+export def get-branches []: nothing -> list<string> {
+    ^git branch | lines | str substring 2..
+}
+
+export def get-strategies []: nothing -> list<string> {
+    $GIT_STRATEGIES
+}

src/nu-git-manager-sugar/git/mod.nu

@@ -2,7 +2,9 @@ use std log
 
 use ../git/lib/lib.nu [get-status]
 
-use ../completions/nu-complete.nu [GIT_QUERY_TABLES, git-query-tables]
+use ../completions/nu-complete.nu [
+    GIT_QUERY_TABLES, GIT_STRATEGIES, git-query-tables, get-remotes, get-branches, get-strategies
+]
 
 # get the commit hash of any revision
 #
@@ -164,9 +166,9 @@ export def "gm repo remote list" []: nothing -> table<remote: string, fetch: str
 
 # fetch a remote branch locally, without pulling down the whole remote
 export def "gm repo fetch branch" [
-    remote: string, # the branch to fetch
-    branch: string, # the remote to fetch the branch from
-    --strategy: string = "none" # the merge strategy to use
+    remote: string@get-remotes, # the branch to fetch
+    branch: string@get-branches, # the remote to fetch the branch from
+    --strategy: string@get-strategies = "none" # the merge strategy to use
 ]: nothing -> nothing {
     ^git fetch $remote $branch
 
@@ -190,7 +192,7 @@ export def "gm repo fetch branch" [
                 error make {
                     msg: $"(ansi red_bold)invalid_strategy(ansi reset)"
                     label: {
-                        text: "expected one of ['merge', 'rebase', 'none']"
+                        text: $"expected one of ($GIT_STRATEGIES)"
                         span: (metadata $strategy).span
                     }
                 }