feat: Add Fluent String helpers (#304)

* add fluent strings helpers

* add more fluent string helpers

* add headline helper

* add test cases for fluent strings

* add test cases for headline function

* modify, according to suggestions

* modify, according to suggestions

* reformat the str file

go.mod

@@ -36,6 +36,7 @@ require (
 	github.com/urfave/cli/v2 v2.25.7
 	go.uber.org/atomic v1.11.0
 	golang.org/x/crypto v0.13.0
+	golang.org/x/exp v0.0.0-20230315142452-642cacee5cc0
 	google.golang.org/grpc v1.58.2
 	gorm.io/driver/mysql v1.5.1
 	gorm.io/driver/postgres v1.5.2

go.sum

@@ -623,6 +623,7 @@ golang.org/x/exp v0.0.0-20200119233911-0405dc783f0a/go.mod h1:2RIsYlXP63K8oxa1u0
 golang.org/x/exp v0.0.0-20200207192155-f17229e696bd/go.mod h1:J/WKrq2StrnmMY6+EHIKF9dgMWnmCNThgcyBT1FY9mM=
 golang.org/x/exp v0.0.0-20200224162631-6cc2880d07d6/go.mod h1:3jZMyOhIsHpP37uCMkUooju7aAi5cS1Q23tOzKc+0MU=
 golang.org/x/exp v0.0.0-20230315142452-642cacee5cc0 h1:pVgRXcIictcr+lBQIFeiwuwtDIs4eL21OuM9nyAADmo=
+golang.org/x/exp v0.0.0-20230315142452-642cacee5cc0/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
 golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
 golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=