feat(shell): add unknown_indicator parameter (#2649)

* Add default config parameter for shell

* Update docs for shell default parameter

* Change parameter to more obvious name

src/configs/shell.rs

@@ -13,6 +13,7 @@ pub struct ShellConfig<'a> {
     pub ion_indicator: &'a str,
     pub elvish_indicator: &'a str,
     pub tcsh_indicator: &'a str,
+    pub unknown_indicator: &'a str,
     pub disabled: bool,
 }
 
@@ -27,6 +28,7 @@ impl<'a> Default for ShellConfig<'a> {
             ion_indicator: "ion",
             elvish_indicator: "esh",
             tcsh_indicator: "tsh",
+            unknown_indicator: "",
             disabled: true,
         }
     }

src/modules/shell.rs

@@ -24,7 +24,7 @@ pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
                     Shell::Ion => Some(config.ion_indicator),
                     Shell::Elvish => Some(config.elvish_indicator),
                     Shell::Tcsh => Some(config.tcsh_indicator),
-                    Shell::Unknown => None,
+                    Shell::Unknown => Some(config.unknown_indicator),
                 },
                 _ => None,
             })
@@ -36,6 +36,7 @@ pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
                 "ion_indicator" => Some(Ok(config.ion_indicator)),
                 "elvish_indicator" => Some(Ok(config.elvish_indicator)),
                 "tcsh_indicator" => Some(Ok(config.tcsh_indicator)),
+                "unknown_indicator" => Some(Ok(config.unknown_indicator)),
                 _ => None,
             })
             .parse(None)