refactor: struct tags (#94)

* refactor(struct_tags): finally my hands got to this

* feat(struct_tags): trim output

* feat(struct_tags): add :GoTagClear

* docgen

* refactor(struct_tags): error on out-of-bounds

* feat(struct_tags): add support for working with multiple tags at the once

* test(struct_tags): test both possible inputs

* refactor(struct_tags): add type annotation, dont force write

* refactor(struct_tags): optimization ig

* docs: fix

* fixup! refactor(struct_tags): add type annotation, dont force write

* task docgen

---------

Co-authored-by: Oliver <1571880470@qq.com>

spec/fixtures/tags/add_many_input.go

@@ -0,0 +1,11 @@
+package main
+
+type Test struct {
+	ID      int
+	Name    string
+	Num     int64
+	Another struct {
+		First  int
+		Second string
+	}
+}

spec/fixtures/tags/add_many_output.go

@@ -0,0 +1,11 @@
+package main
+
+type Test struct {
+	ID      int    `test4:"id" test5:"id" test1:"id" test2:"id"`
+	Name    string `test4:"name" test5:"name" test1:"name" test2:"name"`
+	Num     int64  `test4:"num" test5:"num" test1:"num" test2:"num"`
+	Another struct {
+		First  int    `test4:"first" test5:"first" test1:"first" test2:"first"`
+		Second string `test4:"second" test5:"second" test1:"second" test2:"second"`
+	} `test4:"another" test5:"another" test1:"another" test2:"another"`
+}

spec/fixtures/tags/clear_input.go

@@ -0,0 +1,11 @@
+package main
+
+type Test struct {
+	ID      int    `json:"id"      yaml:"id"      xml:"id"      db:"id"`
+	Name    string `json:"name"    yaml:"name"    xml:"name"    db:"name"`
+	Num     int64  `json:"num"     yaml:"num"     xml:"num"     db:"num"`
+	Another struct {
+		First  int    `json:"first" yaml:"first" xml:"first" db:"first"`
+		Second string `json:"second" yaml:"second" xml:"second" db:"second"`
+	} `json:"another" yaml:"another" xml:"another" db:"another"`
+}

spec/fixtures/tags/clear_output.go

@@ -0,0 +1,11 @@
+package main
+
+type Test struct {
+	ID      int
+	Name    string
+	Num     int64
+	Another struct {
+		First  int
+		Second string
+	}
+}

spec/fixtures/tags/remove_output.go

@@ -1,11 +1,11 @@
 package main
 
 type Test struct {
-	ID      int    
-	Name    string 
-	Num     int64  
+	ID      int
+	Name    string
+	Num     int64
 	Another struct {
-		First  int    
-		Second string 
-	} 
+		First  int
+		Second string
+	}
 }